modpodge
Modpodge is available in matte, shiny, and sparkle finish. It's great for decoupage and giving a clear finish to other projects, but keep in mind that it's not water-proof. Use a clear sealant if you want a more durable finish.
brushes
Brush Sets are widely available at craft and art supply stores. Random tip: if you're painting bleach onto clothing (or anything else), use a brush with synthetic bristles.
clear sealant
There are several brands available. Krylon makes a low-odor spray formula that's nice if you're working indoors.
There are also paint-on glazes available.
acrylic paint, textile medium
There are several brands of acrylic paint, and from my experience, they are all very similar to one another. Some of them differ slightly in price. Most brands make textile medium. Mixing in textile medium will make the paint flexible and permanent when applied to fabric.
fabric paint
If you don't want to deal with the business of mixing paints, you can buy fabric paint which is specifically made to be applied to fabric. Same basic premise as above. Lots of brands, all of them pretty similar.
textile inks

Some larger craft stores will carry the Speedball textile inks. I ordered mine from Dick Blick because they carry a set of 6 basic colors.
Both Dick Blick and MisterArt.com
carry other brands of textile inks like Jacquard, Permaset, and Union.
screenprinting kits
The Speedball screen printing kit is a nice start-up set. Kit includes a 10 in. x 14 in. screen frame, fabric squeegee, 4 oz. bottle of screen filler, 4 oz. bottle of drawing fluid, 4 oz. bottle of Diazo Photo Emulsion, 1/2 gram of Diazo Sensitizer, no. 6 round brush, and instruction book. *This kit does not include ink.

Dick Blick carries the Speedball kit and their own kit, which is quite a bit more expensive, but includes ink and supplies for several screens.
or browse these sites
LoewCornell is currently offering $5 off any order of $50 or more. Offer Expires 3-31-06