AVCHD native editing has been added to CS4, but is not supported for the older PPro 2.0 that predates MPEG-4 cameras.
You must convert the H.264 (AVCHD) footage to an avi file format that Premiere can recognize and work with. Do an internet search for "AVCHD to avi" and you should find some free or inexpensive software solutions to do this. Some cameras come with a utility on CD, so check that as well
Jeff Pulera
Safe Harbor Computers
http://www.sharbor.com