If you have upgraded your iPhone or iPod touch to the latest firmware 3.1.3 without giving any heed to the repeated cries from the dev-team and the others that the updated firmware will create problems while jailbreaking and unlocking it. Luckily, you can now Jailbreak and Unlock your updated iPhone or iPod touch OS 3.1.3 with redsn0w 0.9.4 OR in this case, with Sn0wbreeze v1.4 which the ih8sn0w team released just a day ago to enable jailbreak for the updated firmware.
Download iOS/iPhone firmware for iPhone (2G, 3G, 3Gs and 4), iPod Touch (2G and 3G) and iPad
Important
Now you can do untethered Jailbreak of your iPhone 3G/3Gs running latest firmware 3.1.3 with "Spirit".
Step by Step iPhone and iPod Touch (All models) Firmware 3.1.3 Jailbreak Guide Using Spirit
I myself had problem downloaded the latest Sn0wbreeze because of the slow server speed (it literally went down to 8kbps on a 1Mbps connection!)
So here’s the direct download link for those who want to try Sn0wbreeze to jailbreak and unlock their iPhone 2G, 3G and 3Gs OS 3.1.3: