Craftacular - The craft wiki! tutorials, articles and patterns, editable by the public.
Cre.ations - A place to share your projects, and post instructions if you want.
Instructables
GURL - Everything from knitting to zine making!
The Backseat Kiss - Tutorials that will have your ROTFLing
Not Martha - Lots of free how tos! Some really cute knitting patterns.
Etsy Labs - A variety of tutorials from lovely crafty peoples!
Supernaturale
LJC
OneHourCraft - Craft blog with some tutorials.
CraftBits - Wide variety of simple craft projects.
The Duck Tape Club - Cool project tutorials for duct tape!
J Caroline Creative - Free projects and tutorials for clothing and accessories.
DIY Network - Lots of free craft tutorials!
Martha Stewart - Free craft projects from the Queen of Craft.
Craftzine
Adorn
Quidnunc
LimeHippo
Udandi
Oh My Stars
Cut Out and Keep - A crafty community for making and sharing step-by-step tutorials.
Digs
Creativity Portal
N.E.E.T.
Naughty Secretary Club - 100 super quick crafty ideas
Curbly
The Anticraft
DIY Guide to LRPing - lots of interesting craft ideas
Whip-up - Crafty blog with tutorials.
Crafty Chica - Free tutorials and projects.
The Sampler - Cool promotional tool for crafters, with a How To section.

Craftster - lots of tutorials by forum members. Tip: due to the massive amount of information, if you want to find posts with a tutorial, use the search feature and look up "tutorial" or "tut"

Here are some links to helpful and popular Craftster tutorials:
CLOTHING
flamenco skirt tutorial
t-shirt dress with paneled skirt
halter dress from sheets
mini dress from gigantic t-shirt
5 minute halter t-shirt recon
Grecian style tank from skirt
men's buttondown into girly cap-sleeve shirt
skirt with godets from a pillowcase

ACCESSORIES
the JORDY bag!
fairy wings
socks to armwarmers
pillowcase into apron
super easy kitty hat
felted mittens from a wool sweater
metal handled handbag
arm/wrist band mini purse
boxy bag with handles
Chinese take-out box purse
The Dead Cat bag ;)
Cut-out design bag
Hipslinger / fannypack bag
gathered bag
mini duffle bag
googley-eyed Monster purse
plaid n pyramid bag
reversible handbag
zipper topped tote bag
adding a zipper pocket to a bag
snap wallets
slotted wallet
zipper pocket tutorial
zipper top cosmetic bag

What The Craft - duh! :) t-shirt reconstructions, sewing, and more!
Fitz Patterns - Cool free patterns.
Thread Banger- DIY fashion and sewing instruction videos.
T-shirt Surgery on Livejournal - Community for sharing projects made from t-shirts, with tutorials from members.
Tudor Links - OriginalVictorian and Edwardian period patterns
Red Dawn - Nice collection of tutorials for constructing clothing for costumes.
Vintage Sewing - Free vintage sewing books in the public domain.
Savvy Seams - Free sewing patterns for clothing, accessories and housewares.
BurdaStyle - Nice open source patterns and how-tos, and a SewPedia for all those funny sewing terms.
Needle N Thread - Resources for hand embroidery, with video tutorials.
Sew News - Has some free patterns and designs available for download.
Threads - Website for the print magazine has a lot of articles with tips and tricks for sewing clothing.
Corset Generator - fill out your measurements, and get a corset pattern customized to your body!
Sublime Stitching - some basic embroidery stitches and some embroidery tips!
Embroidery Resource - Some free embroidery pattern downloads + hints and tips.
Futuregirl - A few handy embroidery and handsewing tutorials.
BurdaMode - Several free patterns from one of the better pattern companies.
Amy Butler - Free downloadable patterns.
Hancock Fabrics - More free patterns!
Sewing.org - Free sewing projects, tips, and more.
Sew Trendy - Sewing projects aimed at teens.
Fabricland - Free fleece projects.
Ericas - Variety of free patterns and sewing projects.
Etherwork - Pj pants with pockets and a few more tutorials.
Totally Stitchin' - Some easy sewing projects.
Generation T - Two free projects from the book!
Pattern Bee - Free vintage patterns - quilting, sewing, and embroidery.

Some individual tutorials:
CLOTHES
Harajuku Punk Shirt tutorial by Diana Eng
Aline skirt tutorial
Shorts from pillow cases tutorial
How to draft a skirt pattern
Alexander McQueen kimono top pattern
Junya Wattanabe dress pattern
"Unfinished" dress pattern by Martin Margiela
Wrap skirt tutorial
Another wrap skirt tutorial
Pants or Leggings tutorial
Shawl Collared Blouse pattern
4 interesting gown patterns
Undies tutorial!
Harem pants
peasant top pattern
Historical Chemise / Nightgown pattern
Reversible tube top
Jeans to ruffled skirt
Babydoll top
Twirly Skirt tutorial

KIDS/BABIES
Baby bib tutorial
Baby footies
Super simple shorts for toddlers
Cloth Baby shoes
Baby booties

ACCESSORIES
Mini Bowling Bag tutorial
Native American style leather mitts
Fleece Mittens
Rag Flower Broach
Zippered Pouch
Needle Felted cuff
Quilted Tie-Strap Bag
Mitered squares and striped patchwork bag
Fabric head band
Tote bag tutorial
Quilted wallet tutorial
Dishtowel totebag

MISCELLANEOUS
Pointy Kitty Stuffy Pattern
Chibi kitty and bunny pattern
Popcap pincushion tutorial
Grocery Bag Dispenser
Felt garland and free quilt pattern downloads
Video for gathering with a sewing machine

Knitting Help - Videos of all the basic and some more advanced techniques of knitting, great for those that learn visually!
Knitting Pattern Central - Links to free knitting patterns.
Crochet Pattern Central - Links to free crochet patterns.
Knitty Gritty - Videos and patterns from the show!
Joy of Spinning - Information on spinning your own yarn, whether that be using a spindle or a spinning wheel. There are some instructional videos and lots of useful information to help you learn about spinning.
Knitty - Free online knitting magazine. Patterns for all difficulty levels, and great articles to help you learn more about knitting.
Stitch n Bitch - A few free patterns from Debbie Stoller, author of Stitch N Bitch!
Magknits - Some cute free knitting patterns - cardigan, scarf, felted ghost and more.
Naughty Needles Knitting

Some individual tutorials:
Silver's Sock Class - Excellent tutorial for knitting socks! Great for those attempting to knit their first pair!
Seamless Single Crochet
Navajo 3 Ply (spinning)
Crochet a flower
Knitted slippers
Vintage vertical stripe crocheted blanket
Spindle socks
Spool Knitting
Crocheted hair band

**Thanks to kellesbelles for her help finding these & many other links!

Leah Kramer - a bead project and free beading software

Some individual tutorials:
Metal ring/ pendant tutorial
Beaded Flower Pendant
Button Bracelet
Make your own shrink plastic charms

Violette's Folk Art - Some nice tutorials, focused a little more on the artsy side of things.
Scrapjazz - Supply store with community forums, tutorials, and more.
Scrapbook - Scrapbooking store with forums, gallery, and a library of free resources.

FamilyFun - Lots of free arts and crafts project ideas.
PCCrafts - Content is a bit oriented towards selling their partner sites craft supplies, but they have some nice family oriented craft ideas.

Glass Attic - An incredible amount of information for people interested in polymer clay.
Polymer Clay Central - Lots of free tutorials for polymer clay techniques.

Some individual tutorials:
polymer clay bird tutorial
polymer clay panda charm tutorial
polymer clay strawberry or cherry charm tutorial
polymer clay octopus charm tutorial
polymer clay domokun tutorial
polymer clay lollipop tutorial
polymer clay cupcake tutorial
polymer clay snowman and candycane tutorial
polymer clay jackolantern tutorial
poymer clay fortune cookie tutorial
polymer clay candy apple tutorial
polymer clay cake tutorial
polymer clay Jack Skellington tutorial
polymer clay sushi cane tutorial
polymer clay sushi tutorial
polymer clay rose tutorial
polymer clay flower cane tutorial
polymer clay star tutorial
polymer clay FAQ

Re: A guide to reproduction - free, downloadable zine with a good tutorial for screenprinting.
Bleach + Stencilling - bleaching is one of my favorite embelishment tools, this technique looks really cool.
Leaf Printing
Secret room bookcase - I've always wanted a bookcase that reveals a secret passageway!!
Make your own clothing labels tutorial 1
Make your own clothing labels tutorial 2
Make your own clothing labels tutorial 3
Make your own clothing labels tutorial 4