Trying to update friends iPod and the update hasn't progressed in over an hr. What...

[Wee-Wah]

...to do? We are trying to update my friend's iTouch. The update hasn't progressed at all and it's been over an hour. It's stuck at the halfway point. Should I leave it? If I unplug it, we'll have to start over and we've already done that once. I'm not sure what's up with it. If any one has even a suggestion, that would be most appreciated. Thanks in advance!