Update 10/10/2010!

The latest jailbreak is out called Limera1n. It works for iPhone 3GS, iPod Touch 3G, iPhone 4 and iPod Touch 4G on any firmware 4.0 or higher. It will also jailbreak your iPad on 3.2.2. See this article to learn more.

Sunday August 1, 2010, Comex released what has to be the easiest most idiot proof jailbreak ever! This is a web based jailbreak meaning you do it all on your iPhone. That’s right you don’t hook it up to your computer. Just open Safari on your iPhone and goto http://www.jailbreakme.com and slide to start the install. In about five minutes you’ll have Cydia. This jailbreak works on almost all iDevices. It works for:

* iPod Touch 1G on 3.1.2
* iPod Touch 1G on 3.1.3
* iPod Touch 2G on 3.1.2
* iPod Touch 2G on 3.1.3
* iPod Touch 2G on 4.0
* iPod Touch 3G on 3.1.2
* iPod Touch 3G on 3.1.3
* iPod Touch 3G on 4.0
* iPad on 3.2
* iPad on 3.2.1
* iPhone 3G on 3.1.2
* iPhone 3G on 3.1.3
* iPhone 3G on 4.0
* iPhone 3G on 4.0.1
* iPhone 3G[S] on 3.1.2
* iPhone 3G[S] on 3.1.3
* iPhone 3G[S] on 4.0
* iPhone 3G[S] on 4.0.1
* iPhone 4 on 4.0
* iPhone 4 on 4.0.1

Be sure to backup your SHSH blobs with tiny umbrella here before you jailbreak. Here is my YouTube video of doing this jailbreak on my iPhone 4 about an hour after it was released. Easy as pie and piece of cake. If you are undecided yet another reason to jailbreak is My3G has already been released. This app, only available if you jailbreak, allows Facetime to work over 3G. Take that Apple and ATT! There also is MyWi which turns your iPhone into a wifi hotspot so any wireless device can use it as a router. Connect your laptop or PC to the internet through your iPhone anywhere anytime :)
Jailbreaking does void your warranty with Apple, but IMO that is worthless anyway. Remember, you can almost always restore your iPhone and start over.