Highly likely since all the Canon SDLRs use the Canon Digix processor.
H.264 is a standard that Premiere well supports.
The only thing that I think is unknown is Canon's new AVC-Intra mode (they call it "I" mode). But I think that's only on the 7D and higher with the Digix 5 processor.
It should just work (TM) since Intra (aka I-frames) is the basic building block of H.264 (B and P frames being the others).