The 3G is already on a baseband that cannot be unlocked so to unlock that you would need to do the ipad baseband thing which isnt very reliable right now.
Thanks for all of your help xcar98. One more question if you don't mind, in Cydia on the home page should it tell me that I have my SHSH versions saved?
x98car, do I need custom firmware to update to 4.0 using Tiny Umbrella, or do I just need to download the firmware from some where, and save to my desk top. then just point to the saved firmware when doing a restore, is that correct? This restore will be for the 3gs 3.1.3 When restoring using Tiny umbrella do I just highlight the firmware version I want to restore to then click on TSS? then point to the 4.0 saved firmware? Also can you give me a link for down loading 4.0 firmware?
No you dont need a custom firmware You would just download the firmare. Run tiny umbrella and start the TSS server. Then you can shift-click restore to the firmware you downloaded by pointing iTunes to it. You can find firmware downloads above in the downloads section.