Hey there Deeneelee
My Itunes crashes on syncs and my Iphone ceases to be recognized by the pc after that...
The bad news is that I can't find a way to fix this...
Now... the good news!
Trying to find a solution I stumbled uppon a little software calle wi-fi sync
You can purchase it in cydia for 9.99$ (you can find a cracked repo if you search google)
You install it on the iphone thru cydia and install a software in you pc/mac
I am now syncing my iphone with itunes over my wifi with no problems at all
here is the link to wi-fi sync's website http://getwifisync.com/
Hope that helps!