UPDATE: You can work around by doing a backup first, jailbreaking, and then restoring from backup (which just copies settings/etc over). Stays jailbroken. If you have a pre-jailbreak backup apply that to fix.
People on twitter are saying if you jailbreak from jailbreakme.com, and then do a full restore, you will get FaceTime/MMS functionality back. Unconfirmed
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.
UPDATE: You can work around by doing a backup first, jailbreaking, and then restoring from backup (which just copies settings/etc over). Stays jailbroken. If you have a pre-jailbreak backup apply that to fix.