In Vista no there isnt a way. Not that i know of. You will know when Hibernation is done cause you put it in Hibernation for a reason right? Cause you no longer plan on using the PC at that moment. So really what is the point of seeing it go into Hibernation i you dont plan on using it?
If you plan on waking it from Hibernation as fast as you put it into Hibernation you should consider StandBy over hibernation. It will cause less stress on your system.