LiveClock, a tweak by Ryan Petrich, that modifies the iOS clock icon to display the current time, and shows the seconds arrow move all in realtime. Cool tweak for your iPhone. Your iPhone has to be jailbroken before you can install this tweak.
This tweak for iPhone is completely free, just have to add the correct repository.
Check out this video on how it works:
http://www.youtube.com/watch?v=Kf5Ugo9Chk8&feature=player_embedded