Folks behind the pwnagetool have released its updated version that allows you to jailbreak your iPhone. I would only recommend following this method if and only if your iPhone relies on carrier unlock. Simply follow these instructions to jailbreak your iPhone using PwnageTool method.
Note that if your iPhone does not relies on carrier unlock, follow the much simpler iPhone 4.3.3 Redsnow method.
First, download pwnagetool 4.3 for the mac from this torrent. Then download the iOS 4.3.3 IPSW for iPhone. Move both of the downloaded files to your desktop. Fire up Pwnage Tool in “expert mode” and select iPhone from the three images being shown.
Browse for the iOS 4.3.3 IPSW and then select build. This will create a custom iOS 4.3.3 firmware (pre jailbroken) for your iPhone. In case you are not using with AT&T, you should preserve the old baseband. Do that by checking “Active the phone” option (found under the General button).
You will now be told to make your iPhone enter DFU mode. Do this by:
* Hold Power and Home buttons for 10 seconds
* Now release the Power button but continue holding the Home button for 10 more seconds
* You iPhone should now be in DFU mode
Now start iTunes, and select your iPhone from the left sidebar. Press and hold the alt key and click on the “browse” button. Now, browse for the custom firmware you created in the previous step iTunes will then flash it to your iPhone.
Then you will also need to unlock it. You can do it by following this guide – iPhone 4.3.3 ultrasnow. Supported basebands are – 01.59.00, 04.26.08, 05.11.07, 05.12.01, 05.13.04 and 06.15.00