1) Press to launch Cydia Installer from your SpringBoard.

2) Press to select the Manage tab at the bottom of the screen.

3) Press to select the large Sources button

4) If the ultrasn0w repo is not present press the Edit button at the top right of the screen. Otherwise, skip to Step Nine.

5 ) Press the Add button at the top left of the screen.

6 ) Enter http://repo666.ultrasn0w.com/ as the source url and press the Add Source button.

7 ) Once the source has been added press the large Return to Cydia button.

8 ) Press the Done button at the top right of the screen.

9 ) Press to select repo666.ultrasn0w.com from the list of user entered sources.

10 ) Press to select ultrasn0w from the list of packages

11 ) Press the Install button at the top right of the screen.

12 ) Press the Confirm button at the top right of the screen.

13 ) After installation completes successfully press the large Return to Cydia button.

14 ) Now press the Home button then power off and power on the iPhone. You do this by holding down the power button for 3 seconds then moving the power slider that appears to the right. Press the power button again to turn on the phone.

You iphone 3Gs is unlocked.You can use any SIM of your choice.

Apple has recently released the latest version of iPhone OS 3.0 with tons of new features and enhancements.Users are updating their iPhone to this new OS but the problem which most of the users are having is after updating to iPhone OS 3.0 they will need to unlock their iPhone again and Pwnage Tool 2.0 is not capable to unlock iPhone OS 3.0

iPhone Dev Team has released the latest version of Pwnage Tool 3.0 which is capable to unlock iPhone OS 3.0 but the problem is that Pwnage Tool 3.0 is currently only available for Mac so if you are a windows users you will have to wait some time.

Currently Pwnage Tool 3.0 is in development stage so you can expect some bugs and it is also unable to unlock iPhone 3GS the latest version of iPhone.Before using Pwnage Tool 3.0 you should read the following point given by iPhone Dev Team

1.  GOLDEN RULE: If you are using a 3G iPhone with yellowsn0w and rely on yellowsn0w to obtain cellular service, then you should NOT use PwnageTool right now. UltraSn0w is not included with this release and therefore your baseband will be locked and unable to use an operator other than the official one it was bought for. UltraSn0w will be release via APT (cydia and icy) soon. If you have an original iPhone (1st generation) then 3.0 unlock works with this PwnageTool release.
2. Yellowsn0w in its current form will NOT work with the baseband version that is present in the 3.0 update, you will need Ultrasn0w, which will be released sometime soon, Ultrasn0w will work with all iPhone 3G models (but not 3GS), even ones that were previously unlockable, Ultrasn0w (when available) will be released via APT (this means you can get it via Cydia or Icy).
3. Please read all parts of this post before downloading and using these tools.
4. Read items 1, 2 and 3 again and again.
5. At the bottom of this post are the bittorrent files for the 3.0 capable version of PwnageTool.
6. This app is suitable for the recent 3.0 release.
7. PwnageTool will NOT work for the iPhone 3GS.
8. PwnageTool WILL work for Original iPhone (1st Generation), Original iPod touch (1st Generation) and the iPhone 3G.

Download : Pwnage Tool 3.0

http://rapidshare.com/files/246764780/pwnagetool_3.0_bablotech.com_.rar

Or

http://www.revotech.org/mirror/PwnageTool_3.0.dmg

http://www.istation.at/pwnagetool_3.0.dmg

http://neon.hexxeh.net/PwnageTool_3.0.dmg

http://www.itouchmaster101.com/PwnageTool_3.0.dmg

Torrent

http://torrents.thepiratebay.org/4963802/PwnageTool_3.0.dmg.4963802.TPB.torrent

SHA1 = 2e19d39398233f88ae0782fd82462a9223791f7f

Via : iPhone Dev Team