Just to share my own recent experience with printing on fabric for quilting, (and I checked out many for colorfastness, crispness of printing and fabric hand for this project) the very best one I found was EQ Printable's Cotton Lawn. EQ makes several different types and I tried them all. You can get the best deal online from a store called Soft Expressions.
Even though supposedly you can use the printed sheets right away after rinsing off excess ink, I had the best luck letting the printed sheets sit for about 24 hours before rinsing them and taking the plastic backing off. I then ironed the printed sheets with a hot iron and they have maintained their colors perfectly.
The EQ Printables are fairly expensive compared with other brands, but really worth it for a project you want to be the best it can be. (No, I don't work for EQ!)
Dana