How can I backup all my jailbroken iPhone apps saves before restoring to new firmware?

I have a jailbroken iPhone (3Gs, iOS 4.0.1, bb 5.13.04). I want to get jailbroken & unlocked 4.3.1 , but I cannot do it in other way than restoring from custom pwned firmware, so all my saves and app data will be erased.

How can I back up all my app data and games saves to restore them after firmware upgrade?

Thanks in advance.

There is an insanely detailed step by step process on how to do this using the cydia app appbackup on http://applemonday.com/2011/04/jailbreak-data-apps-ios-appbackup/ which basically grabs all your app data and puts it in one folder for you to ssh into and get.

PKGBackup ($7 from Cydia) will back up all your settings to Dropbox.