8110 - GPS
8120 - WIFI
8130 wont help you as its CDMA but has GPS
all support 8gb microSDHC, video recording (must have a media card) as well as a whole slew of other updates.
Compare Phones (Phone Scoop)
The 8110 is identical to the 8120 with the exception of what i listed up top. 8110 has GPS no WIFI, 8120 has WIFI, no gps