Here is an excellent webpage made by Stinsonddog! It covers just about every aspect of GPS and mapping on the 8800!
Stinsonddog’s massive GPS area
Basically you have the following options for GPS on the 8800:
1. Telenav Their website here
2. BBMaps Their website here
3. Wayfinder Their website here
4. Garmin Their website here
5. Telmap Their website here
6. Skylab Their website here
7. Google Maps Mobile Their website here
8. Nav4all Their website here