This is BY FAR the easiest jailbreak ever! THANK COMEX!
Ok so let's begin:
1. Update to iOS 4.0.1 (or 3.2.1 for iPad) in iTunes (must have the latest iTunes. Download here: http://apple.com/itunes/
2. After you've updated to iOS 4.0.1 (or 3.2.1 for iPad), launch Safari on your iPhone (Make sure you're connected to WiFi)
3. Go to this website on your iPhone/iPad: www.jailbreakme.com
4. Slide your finger across where it says "Slide to Jailbreak"
5. Wait while it jailbreaks your iPhone 4/3GS/3G. Shouldn't take long.
6. Within minutes you'll have a jailbroken iPhone/iPad!
Reboot your iPhone (just in case).
NOTE: The iPhone Dev Team will be releasing iPhone 4 unlock shortly (a few final tests). For those on the iPhone 3GS/3G, you may unlock your iPhone 3GS/3G using the Dev Team's ultrasn0w (which still works on iPhone 3G/3GS on 4.0.1). The Dev Team has released Ultrasn0w for the iPhone 4!Directions for iPhone 4/3GS/3G unlock:
1. Once you've jailbroken your iPhone 4/3GS/3G on iOS 4.0.1, launch Cydia. Go to Manage>Sources. Touch on “Edit” and then on “Add”. You will be prompted to enter a URL source. Type in: http://repo666.ultrasn0w.com
and press “Add Source”.
2. After installation is completed. Search for: ultrasn0w
in Cydia and install this application. This app will automatically unlock your iPhone 4/3GS3G so that you can use it with any GSM carrier.
And you're done! You now have an iPhone 4/3G/3GS jailbroken and unlocked on the newest OS 4.0.1!
If anyone has any issues, let me know.