craftgrrl | Acrylic paint on fabric?

Hey everyone, I just had a question about painting on fabric..

As part of an x-mas gift for my boyfriend, I plan on painting a couple of pillowcases to go with his new bedsheets since he's been unable to find ones he likes.
It's simple, just a stripe down the edge of the case to match the sheet colour. I'm just buying two cheap pillowcases from IKEA or something. I'm assuming I have to pre-wash them, however I'm unsure about what paint to use.
I was going to use regular acrylic paint, but do I have to use any special kind? Do I have to add any type of textile medium to it? I want to make sure the paint won't wash out (as he washes his bed sheets obsessively) or fade or any other possible thing that could ruin them.

Any help is greatly appreciated! Thanks.

[edit:] Also, would regular high-tack painters tape work for the edges? I don't want it to bleed...