you can re-jail it with or without ifuntastic. first, try using ifuntastic:
open the app and let it recognize your phone. click on prepare and let it run through it's cycle. let it do whatever it does...it might fail, no big deal (your phone is already unjailed). next, click on the finish button and click on jail. that will "fix" your phone syncing problem.
if that does not work, you will need to download the "sources.list" file from
Here.
create a directory in your home folder called "phonedmg"
also download the jailbreak/iphoneinterface files from
Here.
unzip those into the phonedmg folder as well.
open up the mac activity monitor (in the /Applications/Utilities folder) and make sure itunes and itunes helper
are not running. quit them if they are running.
hook your phone to your mac with a usb cable
open up the terminal application and type in "cd phonedmg" and hit enter to switch into your new folder (caps matter, so put it all in lower case).
type in "./iPhoneInterface" and hit enter to connect to your phone (caps matter, pay attention to upper/lower case).
the prompt will change a bit, that's normal.
type in "cd /System/Library/Lockdown" and hit enter.
type "putfile Services.plist" to replace the factory lock file on the phone; hit enter.
type "exit" and hit enter to exit the iphoneinterface program.
reboot your phone and reconnect to your computer. itunes should now smile at your phone and let you sync