I know there are several others, but since Draw Decals is local to me, I use them and have always been satisfied with their decals.
When worst comes to the worst, I have made my own inkjet decals. Especially for dark decals over a light finish, it is not as hard as many people think. I can often find images of logos and such with a google image search. Light colored decals to go over a dark background color are much harder.