One of the most remarked new features in iPhone OS 3.0, one that works on Apple handhelds old and new, is Find My iPhone (aka Find My iPod touch). This is a super slick way to locate your device after forgetting it somewhere in the house or at the mall or wherever fate chooses to frown upon you.

Although iPod touch users can’t benefit from precise GPS location services and the first generation touch can’t “ping” when commanded, this is nevertheless an invaluable feature.

The one big catch that affects both iPhone and iPod touch owners? You’ve got to have a MobileMe account, which will set you back from $69 to $100, depending on the available discounts, the season and whether you buy your subscription together with a Mac or a la carte.

Assuming you’ve got all of the necessary pieces to this puzzle, here’s how to set up Find My iPhone or, in my case, Find My iPod touch:

1. On your iPhone’s Home screen, tap Settings.
2. Tap Mail, Contacts, and Calendars.
3. Make sure Fetch New Data is set to Push.
4. Select your MobileMe account and turn on Find My iPod touch.

See also:
— How to use Remote Wipe (YouTube)

As has been pointed out by many, a thief or person who just happened across your Apple handheld can defeat Find My iPhone by shutting it off. You make that a lot harder by setting up a Passcode Lock (Home -> Settings -> General -> Activate and then set a Passcode Lock).

Now, if your iPhone is lost, in the house for example, you can command it via email to make a series of “pings,” described by some as a “radar” sound, to help you echolocate it. Also, assuming the device is turned on and somewhere on the grid, you can also locate it via Google Maps.

All of these features are accessible via your MobileMe account online—just log in and click accounts, then Find My iPhone.