xBackup for iPhone is a new jailbreak tweak available in Cydia that allows you to easily create backups of all your jailbroken applications and tweaks. I have personally always dreaded restoring my iPhone and re-jailbreaking to a new firmware since the task has always been so daunting. This program sets out to make that task not so irritating anymore.
xBackup will simply save your backup as part of your iTunes backup. All you'll need to do is open xBackup, tap Backup and it will create a backup of all your Cydia packages and settings. Then sync your iPhone with iTunes. After you're done with that, upgrade or restore your iPhone like you normally would (or use PwnageTool or another custom upgrade method, however you prefer). After you are done jailbreaking again, instead of having to re-download and install all your jailbreak settings, simply download xBackup again from Cydia.
You'll simply have to open xBackup and choose the restore tab this time. You should see your last backup. Just tap it and all your Cydia settings and apps will come back down. If you don't see your backup, you'll need to make sure that you chose to restore from your most recent iTunes backup.
You can also SSH into your iPhone and save your backup somewhere on your computer as well. I'd recommend this for safe keeping.
If you guys give this a try, let us know. xBackup is currently $1.50 in Cydia. Hit the jump for a few more screenshots of xBackup in action!