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 Jailbreak the new iPhone 3G will be called purplera1n.
Ultrasn0w Guide - Unlock (unlock) iPhone 3G - firmware 3.0.
Make sure your phone is with the Firmware 3.0 . and done with the jailbreak redsn0w .
Step 1: Add the repository / source to Cydia or Icy: http://repo666.ultrasn0w.com
(WARNING: it is better, before installing to disable the 3G network on the device: SETTINGS> GERA L> NETWORK)
Step 2: Search for "ultrasn0w" and install!
Step 3: After installation restart your phone and voila!
Just remember, do at your own risk.
via itouchbr
Palm Pre, the phone just to take your first "jailbreak" by an application developer for the iPhone very famous, named Steven Troughton-Smith, creator of one of the first applications for the iPhone, Lights Off. 
The process itself is basically simple and reminds himself jailbreak the iPhone, which uses a vulnerability in DFU mode to run unsigned code.
Despite the limitations, it's just a matter of time before developers have launched their own "App Store" for the device, along with many patches and modifications in design. A release can also be close.
