It should be able to record in mpeg4, which you should be able to load into iMovie. I didn't even know that the evo had the option to record in 3gp.
I've got an old Powerbook G4 and used the freeware, QTAmateur to convert it 3gp to MPEG4 for iMovie. Takes awhile to do a conversion, but other than that, it worked great.