I put this in the turn-by-tun thread too but I think it deserves a thread of it's own.
Mods please delete if this bends any rules, but.....
Navigon GPS app plus Aus/NZ maps are free for SGS 2.2
Steps:
1) make sure you are on 2.2
2) download Market Enabler from market
3) set region to custom 50502
4) search for and install navigon
5) download maps (both countries ~300mb)
-optional-
Download Navigon Fresh (http://www.navigon.com/portal/int/karten_services/fresh.html), and install maps via mass storage
SOURCE: http://forum.xda-developers.com/showthread.php?t=834994