Если под Symbian S60 3rd, то Garmin Mobile XT:
_http://www8.garmin.com/software/GarminMobileXTforSymbianS603rdEdition_42020.exe
+ карты можно найти тут:
_http://4pda.ru/forum/index.php?showtopic=60485
I'm not sure if it's the best GPS app for Nokia, but Ovi Maps used to be pretty good back in the day. It's been a while since I used it, but I think it was decent for its time. Does anyone know if there are any good alternatives out there?