I took the plunge …
Update 1/25/2008 16:20
Unfortunately, the solution to get Locate feature working is not permanent. If iPhone is rebooted or goes into Airplane mode, Navizon will have to be run again to get it working.
Update 1/24/2008 20:54
The Locate feature in Google Map was not working initially. But i found a solution:
… and tried the just released jailbreak for 1.1.3. And, i am very happy to say that my iPhone is now upgraded to iPhone firmware 1.1.3 and running perfectly fine on T-Mobile.