The BlackBerry 8800 does not include a WiFi Radio, instead it has a GPS Reciever. The reverse is true in regards to the 8320 (Curve) as it has the WiFi Radio but lacks the GPS Reciever. Now, the 8820 includes both the WiFi Radio and GPS reciever.
Look at the links below, select all the devices and click compare for full details on each device. BlackBerry 8800 Series Comparison Blackberry 8300 (Curve) Series Comparison