I doesn't back up my iphone 3g and it stuck on restore point and recovery mode in itunes.
Hold the Home + Power button simultaneously for 10 to 30 seconds. Your device should boot into it's original state. If it doesn't, put your device into DFU mode (Google/Youtube how to do so.), and restore your device.
If you don't have a backup you will lose all of your content when you restore. You can reload your apps and music, but other content will be gone.
Retrieving data ...