Release Date: September 2009
List Price: $750 USD
Both of those cameras look much more like digital SLRs in terms of shape (although they're still much smaller than "true" digital SLR cameras).
Instead of looking like a DSLR, the GF1 takes on the boxy shape of a compact camera, leaving out the viewfinder that's available on both the G1 and GF1. It also doesn't include a flexible LCD - the screen is fixed firmly in place on the back of the camera.
Bottom line? The DMC-GF1 is a more portable camera and retains many of the features available on other Panasonic mirrorless DSLRs.
List of Features
Panasonic Mirrorless Cameras