Honestly I think the best way is silkscreening. You can do the separations on photoshop with some practice. Although if you must do transfers, you'll probably get the best results with a printer that does contour cutting like a VersaCamm from Roland using rolled printing material. I'm not sure about smaller printers, I think I've seen people recommend epson printers a lot on this forum. However if you use a desktop printer It would probably be a good idea to get a table top cutter as well so you could contour cut around you're image. That way you're not stuck with a square of transfer paper. Check out Stahls ID or Imprintables Warehouse