Finally Spirit, an untethered jailbreak for iPad, iPhone 3G 3GS, and iPod touch is out for public. Spirit is very simple jailbreak tool, just like Blackra1n, all you need is to just plug your device and launch Spirit and it will automatically detect your device and its version, just click on jailbreak and rest it will do. In order for this to work, you need the latest version of iTunes (9.1.1) available from iTunes.com.
If you currently are using a tethered jailbreak, you have to restore to use Spirit. Do not upgrade if you rely on blacksn0w or ultrasn0w unlock on an iPhone 3G or 3GS .Also before doing jailbreaking your device make sure you’ve taken the backup of your SHSH blobs so that if anything goes wrong you can, however, restore to 3.1.2.