"Assuming you save your passwords on your iPhone (iPod touch and iPad as well), you don't remote wipe it and assuming the person who finds it is a pretty astute hacker, you may want to reset your passwords. PCWorld details how an iPhone can be jailbroken and give up passwords in just 6 minutes."
Jailbreaking and unlocking / hacking into your iPhone's keychain can be done in as little as six minutes. This exposes any passwords that you may happen to store on your device, even if it is locked. An emergency plan to list (in order to change) all important passwords should be at the top of your own personal disaster recovery plan. If your iPhone is lost (or stolen), assume that all your passwords are compromised, and learn to use the Remote Wipe feature within MobileMe's Find My iPhone. And change those passwords!
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"Not everything that can be counted counts, and not everything that counts can be counted." Albert Einstein
Gone in Six Minutes: Your iPhone and Your Passwords
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