Well, I've never seen a doner kebab, so I can't really speak to that... - Edit 1
Before modification by Phelix at 09/09/2010 12:32:33 AM
When it's stuffed into a pita we call it a pita. *shrug*
The meat is one, I'd say. As the word "döner" indicates, it's scraped off rotating grills to put it in the bread, for döner kebab. Pita tends to be different meat, here anyway. And the bread I'd use for pita isn't the same as that for kebab, either, but that may not be the case everywhere. So I guess it is fairly similar, in conclusion. 
But pitas can be made in a variety of ways. First, grilled meat stuffed into a pita with sauce and veggies; secondly rotisseried meat (usually a combination meat, lamb, beef, chicken, pressed into a cylindrical shape) that is shaved into slices and put into pita bread with veggies and sauce; and the third way I've seen pita done was with pre-sliced portions of meat that were heated and put inside pita with sauce and veggies.
The bread is always "pita bread." There might be variation for region or flavors... but it's a six inch round of flatbread.