Find My iPhone helps when AT&T's insurance can't.

"Should you (gasp!) lose your iPhone, you can log into your MobileMe account and have it map out the current location of your iPhone directly within the browser. From there, you’ve got a few options:

* Send a message to the iPhone (with optional alert sound, which plays even when the phone is set to silent), urging people to call you back

* Fire off a kill signal to the phone, which remotely wipes the phone’s data. Don’t worry though: once you get the phone back, one good restore from iTunes and you’re back in business.

...this definitely makes MobileMe’s $99 asking price easier to swallow."

also see: iPhone OS 3.0 beta testers get Find My iPhone