Navizon has released a new version of Navizon called "Navizon Lite" which provides global positioning capabilities to iPhones based on cellular tower triangulation.
The product differs from the full version ($24.99) of Navizon by removing the Wi-fi positioning capabilities. This makes the Lite version accurate to 1000 meters, rather than up to 10-30 meters with Wi-Fi sensing available.
The Lite version is roughly equivalent to Google's My Location feature they recently released for mobile Google Maps. We expect that the iPhone's Google Maps will eventually offer the new "My Location" features that allows you to estimate your global position, but in the meanwhile, Navizon offers a free solution for those who have "hacked" their iPhones to allow 3rd party applications.