Not too many of those. Actually, just one.
DrPepper's Matchcaps is simple re-skin of Bejeweled. Not horribly imaginative, but this press release says it's the first advergame for iPhone (it came out in November 2007). So far, it seems to be the only one.
Fingerfracture is a concept for Vans from Miami Ad School that surfaced a few weeks ago. Just mock-ups for now, but way cooler than a simple re-skin.
Another mock-up: iPhone game controller. Clever and obvious.