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redsn0w is an easy to use, multi-platform, multi-device jailbreaking and unlocking (iPhone 2G only) tool for the iPhone 2G (original iPhone), the iPhone 3G (but not the 3GS) and also the iPod touch (first and second generation). Currently it is available for Windows and Mac OS X (there are some issues using redsn0w with OS X PPC, please use an Intel Mac until we have this problem resolved)

Crap, I am on PPC
 
just download one from somewhere.....

put your phone into dfu mode then your set. no big deal. you can use pwnage tool to help u with that

look on torrent sites for

2G Iphone: iphone1,1_3.0_7a341_custom_restore.ipsw
3G iPhone: iphone1,2_etc
3GS iPhone: iphone2,1_etc
 
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