Do you own an iPhone or iPad and need to jailbreak it ? A couple of tools like PwnageTool, redsn0w and ultrasn0w are the solution you should look for. The latest version of ultrasn0w should do the trick till Apple IOS 4.3.3. You should be able to jailbreak the following :
- iPhone3GS
- iPhone4 (GSM)
- iPod touch 3G
- iPod touch 4G
- iPad1
- AppleTV2G