Yes, it's DDR2 and faster, so it should work. The only way to be sure, of course, is to actually try it, since there are occasionally more subtle differences in RAM that will make a particular brand incompatible, but probably not.
Theoretically, they should work -- however, at least in some cases, they don't.
Crucial.com's memory selector used to list PC6400 as iMac-compatible, but
several forum members reported that they they didn't work and returned the
parts to Crucial. They no longer appear on Crucial's iMac compatibility list.