I’ve seen a lot of Inception web articles (including Wikipedia) say that the third level’s Dreamer was Eames (Tom Hardy). However, Dileep Rao (who plays Yusuf, the Chemist) explains the contrary - the third Dreamer is actually Fischer (Cillian Murphy), although he thinks the team is entering Browning’s dream. :D
I’ll take Rao’s word for it. Buuut then again, there is a lot of evidence supporting the fact that Eames may be the actual third Dreamer. Is Rao ultimately correct?
Note: Don’t read if you haven’t watched Inception yet!
Here’s a pretty thorough article that answers a whole lot of good questions about the movie. Mostly it’s like a guide to the film, as it also includes definitions of the special terms used in “Inception.” :)