Can I turn off passcode using iTunes??

That is a common problem, but, unfortunately, there is not a satisfying way to solve it. There isn't any easy way for the user, but if you take it to an Apple Store Genius Bar for the screen work, they may have a way to back up to your iCloud account if you have one.

No, if you have forgotten the passcode, the only way to turn it off is by following the instructions in http://support.apple.com/kb/HT1212 using the recovery mode.