There is only one free native Symbian option for your Nokia Symbian smartphone if you like to use free GPS maps navigation software. It is Nokia Maps, also known as Smart2go. The site where you can download this application is here. By the way it now officially has been updated for almost all of S60 3rd edition devices (including E61(i), E61i, E65, N73, N76, N93i, Nokia 6120 classic and the ones with Nokia Maps preinstalled - E90 Communicator, N95 and 6110 Navigator), not only N Series as before, but for E Series devices too. Most interesting thing that it is now available for Symbian Series 60 (S60) 2nd Edition devices Nokia N70 and N72. I hope we can install it on 6630, 6680, 6681, 6682 devices too. But this assumption should be proven.
There is more options on free GPS navigation for Symbian: amAze GPS for J2ME devices with Bluetooth GPS receiver which may run on Symbian too, Nav4All the Java-based voice-guided navigation system which supports Bluetooth GPS and integrated GPS in Nokia N95 and Nokia 6110 Navigator devices.