After upgrading to iTunes 10 and 10.2 I noticed that iTunes tends to freeze or hang as soon as I plug my iphone, it will resume working as soon as you unplug the USB connection. Or minutes after the device is connected, but it wouldn’t detect the device.
At first I thought it was a power issue, but then I realized that other software like i-fun-box works just fine.
After some digging I discovered that my “Kaspersky Antivirus” was conflicting with itunes in some way causing it to freeze. closing Kaspersky completely before connecting the device solved the problem for me.
Try closing any antivirus or security software you have, it may solve the issue