Yes while it is charging and if the phone is ON then you can use it just like you would as if it were not charging

 

What do you mean? Isn't it just whatever screen you're using?

Edit: Unless you're talking about not having the screen turn off while charging, even when not in use? If so, then Settings > Applications > Development .. I believe its the 2nd box (off the top of my head, I can't remember for sure)

 

Kaoler Clock in the market can be set to come on when plugging in

 

Well I mean, it doesn't force you into a screen when you charge so I don't see what the problem is. If you would like the desk clock while its charging, all you have to do is go to that app. Simple as that. (If you don't have the screen display to stay on during a charge, then just refer to my previous post on how to make it to stay on)