But can the Dev team be far behind, it has released Pwnagetool 3.1 only for Mac.

Careful not to use this on your iPhone 3GS as it does not unlock your 3GS it is useful only on the 3G.

Steps to a Successful  Unlock:

• Upgrade your Apple iPhone 3G firmware to 3.1 OS.
• Then Download the PwanageTool 3.1 for Mac [Download Link]
• Connect your upgraded iPhone to your Mac
• Then follow the steps. (Almost the same steps as the previous versions)

Now is the most important part of the process, here you have to follow these steps carefully:

1. Installation of  Ultrasn0w completed.
2. Restart your iPhone.
3. Then go to Settings > General > Reset > Reset Network Settings and the Phone Restarts.
4. Then go to Airplane mode, switch it on and off once
5. Then go to the main screen and wait for a couple of minutes and the signals would appear with your network name on the right to it.

And you can enjoy with your iPhone 3G with 3.1 Firmware unlocked.

Note: This is at your own risk.

The most important Tip is for the Ultrasn0w users with Jailbroken iPhones, should not upgrade to 3.1 as they might lock their phones again.

Courtesy engadget.com

New Options in 3.1 OS: As of now

1. "Save a Copy" option for 3G S video editing that lets you retain the original film while saving an edited clip.
2. Rumors of MMS being activated.
3. When you move your icons around the iPhone vibrates.
4. There’s now a VideoEditorController API - Allows third party apps to call up video editing UI.
5. Video picker API