Hi,
I found this link:
http://www.getjar.com/products/11/ChessGoClock
and I think it might be useful for some of you(it is for me)...if you want to have a chess clock with you but you do not want to buy one(as the are sooo expensive-50/60 euros for a simple clock)
I tried it on my phone and it is working fine(I haven't tried it by now in a real game but it looks ok...playable(at least in a rapid chess game-not sure how would it handle a blitz game)