www.stencilrevolution.com is a start. That has good stencil tutorials including some about shirts. If you look in the forum there's even a guide to stencilling shoes.
As for equipment, it's all pretty cheap. If you stencil them on ( a good method, you can give it to a friend afterwards )
You will need:
A shirt. Black or white is best. Cotton is more desirable than synthetics and the thicker the fabric, the better. If it's a new shirt, wash it to allow shrinkage.
A stencil. Some say cardboard, I say make an image on your computer and print it out. Get it laminated and cut it with preferably with a fine craft knife with a handle like a pen ( i think they are called exacto knifes. ).
Failing that, a craft knife. Do not use scissors, they will only suffice for extremely simple designs.
The paint.... unless you want to buy special fabric paint you have to mix acrylic with textile medium. Either way, you can't use a spraycan. Use a roller.
The method.. Stick a piece of thick carboard through the shirt to keep it stiff and stop crap going on the back. Tape down the stencil. If you don't want accidental paint spots in places ( IMHO this can look really cool, but whatever ) put some newspaper over the rest of the shirt.
Get some paint on the roller. Don't be sloppy, apply it evenly. Once you have an even coat, CAREFULLY remove the stencil and tape. Give it a blast with a hairdryer. If you want extra colour-locking power, put a piece of baking paper on it and lightly iron it.
Enjoy.