In Japan I believe you can scan the phone at retail outlets and perform transactions straight from the phone. Now that's awesome! Not the iPhone yet though. Just smart phones. That's what the iPhone needs though!
Here is a list of some seemingly cool apps for the iPhone. Not sure how good, but their descriptions make them sound pretty worthy. Either way, if you are interested: http://makefive.com/categories/technology/technology/the-best-iphone-apps