Lockbox is a password & secret information storage program for the iPhone. It stores passwords for websites (or any system), credit card info, or any secret information you need to keep ready at hand, encrypted on your iPhone.

This looks to be promising. Even better would be if the Wallet software I currently have would produce their own iPhone utility, that would be great. (No, storing the data remotely on a server that I access over EDGE or WiFi is not an acceptable solution).