Micromark.com
They sell a starter set with transfer sheets (8.5 x 11), for either inkjet or laser, fixative, etc. they also sell solvent and setting solutions to help them adhere better.
I've made tons of my own transfers and had no problems with their products.
Edit: or at least they used to. Here is the link to their decaling section - accessories includes the kits for setting/solvent, the paper is, well, the paper
http://www.micromark.com/decaling.html