It only backs up the apps no data, yet. There are alot of ways to do this but this one actually makes a flashable zip file and puts it on you sdcard.
Just flash FlashBack-Installer.zip and open up terminal and type
Run the backup (It takes a minute before it starts going)
Then flash your new rom or whatever and right after flash FlashBack.zip to restore your apps.
Saves alot of time for people who do alot of flashing like me. And this should work with most devices if not all of them. It uses busybox to mount the drives in the updater-script files.
I will be adding more to this so post any ideas or feedback you have.