Ok. Here's what you do.
Go here, and follow each direction in detail.
Jailbreak iPhone 3.1.3 with Redsn0w 0.9.4 | Redmond Pie
If you are confused, LET ME KNOW. You will need to download te following:
?redsn0w 0.94 (from link in tutorial)
?iPhone 2G Firmware 3.1.2 (from link in tutorial)
?iPhone 2G Firmware 3.1.3 Install + Update (from iTunes)
Follow all of those steps, and then get back to me.
AT THR END, and this is important - when you get to the unlocking process for the 2G, do this:
After installing Cydia, it will ask you questions, and to update. Select "Graphical User", and "Complete Upgrade". Let it restart and reboot. Once it does it's thing...*
In Cydia, search for the app ?BootNeuter? and install the app. Open BootNeuter and make sure the settings match are exactly as follows:
Version: 4.6
Neuter: On
Faceblank: Off
Baseband: Unlock
Then tap "Flash" in the upper right corner to unlock.