Jailbreaking the iPhone 3G hit the web. The hacker announced today on her blog that she is ready for use, and officially released on this site , code-named purplera1n.
For now the new tool works on Windows only, and for being a beta solution, because the firmware upgrade to 3.1 due out at any time, it is recommended that you know what you're doing before any procedimentode jailbreak!
The famous hacker GeoHot managed to jailbreak the iPhone 3G.
Although the new iPhone come with a new "security" that prevents the downgrade to previous firmwares. Hacker posted on his blog "In sn0w in this summer ..." with a picture of MSDOS (windows) , The iBoot the new Iphone 3G, which indicates that he found an exploit in iBoot.

In the picture you can see also another site at the very end called " purplera1n.com "Probably the new Jailbreak the iPhone 3G will be called Purplera1n.
The Group Dev-Team has released updated and redsn0w for Windows. 
- I install the 3.0 firmware your device ;
- Pull the redsn0w ;
- Open redsn0w and click Browse. There select the 3.0 firmware that you used on your device;
- Wait for the recognition of the firmware and click Next;
- Choose the options you want to apply (install Cydia for example) and click Next;
- The next step is to make sure your device is plugged in and turned off. Turn it normally and then click Next;
- Now it's gone through: Press the Power button for 3 seconds and hold the Power, also press the Home button for 10 seconds, and then hold the Home button, release the Power button for a few seconds until the device into DFU;
- Wait for the installation, wait for the device restart (Jailbreak already) and click Finish.
via iTouchbr!