I use a bluetooth gps reciever I have sprint for service and lets just say there service sucks in some areas. Honestly rootlinux the reason why i use the garmin I've never had any problems with it I do a lot of traveling I have tried the telenav and tomtom but I haven't found anything better then garmin. here is a link for the garmin bluetooth reciever I use highly recommend it
http://cgi.ebay.com/ws/eBayISAPI.dll...%3DI%26otn%3D2