I bricked my Iphone the first time I ran the jailbreak. Here is what I did to get it working again.
1. Start itunes and plug your iphone into your computer. Nothing will happen right now, just do it.
2. With your iphone plugged in and itunes started hold down the home key and the top button.
3. Keep holding down both buttons during the reboot and blank screen. Don't let go until you see a disk and a usb cable.
4. Select restore from itunes.
Full restore failed for me. I'm trying this procedure: http://forums.macrumors.com/showpost.php?p=10298203&post...