Geohot has just released limera1n for Mac to jailbreak iPhone 3GS, iPhone 4, iPad, iPod Touch 3G and the new iPod Touch 4G.
This guide will provide you step-by-step instructions to jailbreak iPhone 4 and iPhone 3GS using limera1n.
Here are some important points to note before you proceed.
This guide is only for iPhone 4 and iPhone 3GS users.
Please note that jailbreaking your iPhone may void your warranty and hence proceed with caution.
Do not forget to backup your iPhone before you proceed. You can refer to this post for instructions on how to backup your iPhone.
Limera1n supports iOS 4, iOS 4.0.1, iOS 4.0.2 and iOS 4.1.