How do I get a callback within my TableViewCell, inherited from UITableViewCell, when the device orientation changes?

Question

Hello,

I'm in the following situation:
I created my own TableViewCell (inherited from UITableViewCell) with new labels. It works really good when the device is in portrait mode (I designed the frames of the labels based on 320x480). Now the problem is when I turn the device in landscape orientation I haven't got a method which adjusts the frames.
So I'm searching for a callback which runs in when I turn the device to landscape/portrait mode.

I'm not (yet) familiar with the NSNotificationCenter; so if the solution has anything to do with it, please explain a bit further ;)

Thanks Lars Petersen