The Verizon iPhone, which was announced today, has slightly relocated buttons.
The newly revised CDMA antenna notch has pushed the volume and mute controls a bit down from the GSM version. This means that a lot of current iPhone 4 cases probably won't be an exact fit for the Verizon iPhone. However, third-party manufactures will most likely have compatible cases in stores before the February 10th launch date.
via Engadget