Printable transfer paper?

I have a friend that is looking to design his own transfers for his Space Marine chapter. I know that Local Ork had mentioned an army that used them for the sails of Raiders. I am looking for (preferably) a brand/retailer here in the US that carries them. Thanks in advance.

May years ago I did ork decals from free samples of "Tattoo paper". It isn't the same stuff but works (I just had heckload of "free sample" sheets)...

Here is tutorial on BoLS...
http://www.belloflostsouls.net/2010/12/tutorial-custom-decal-sheets.html

And here is US retailer.
http://www.decalpaper.com/Default.asp

[edit]
Hey, I still have some! Awesome.

Thanks L_O, I'll pass it on.

I have some of this paper too, don't forget that you will need a sealant after you've printed it otherwise you'll destroy it while trying to apply it.