I found it out!
this post was helpful:
http://www.modmyi.com/forums/file-mo...game-data.html
theres lots of files to backup:
**when restoring, copy the file over and set permissions to 775**
saved games/ Application Data
/private/var/mobile/Applications/big long number/Documents
Most of the time your data is in here, just one file. A .db (database) file or sometimes a file called "save"
/Library/Themes
if you have any themes, for winterboard
default Apps: (youtube, call history, webclips etc)
/private/var/mobile/Library
/var/mobile/Library/ here too?
relatively small directory, mine is 20mb
NES Roms (if you have em):
/var/mobile/media/ROMs/NES/
Cydia Apps
/Applications
Also, do any of your cydia applications dL things themselves? like dTunes or mxTube? if so you'll want to backup those files as well
If I were you, I'd back up everything just in case. Then worry about finding the files you need when it comes time to restore, if you need to. (apparently Itunes backs up these files..but doesnt work a lot of the time for me so that's why I looked into this).
Just make sure to skip your music directories: /private/var/mobile/Media/iTunes_Control/Music and /var/mobile/Media/iTunes_Control/Music/
you can skip your photos as well if you want: /var/mobile/Media/Photos and /private/var/mobile/Media/Photos