By setting up the free Find My iPhone (or iPad, or iPod touch) service, owners of iOS devices can not only locate their misplaced gadget on a map, but also remotely lock it or wipe all of the onboard data if need be. It's one of the iOS's most valuable features, but it's also one that most people don't know about until it's too late.

While this previously required a subscription, Apple has recently opened the service up to owners of the most recent versions of the iPhone and iPod touch. So, if you've recently bought an iOS device or given one to a family member, it's a good idea to set this feature up.

Step 1: Check your device(s)

The Find My iOS device service is free to all MobileMe subscribers, but if you're not signed up for Apple's $99 per year service, don't give up all hope: if you have an iPhone 4, fourth-generation iPod touch, or any model of iPad then you can sign up for Find My iOS device for free. And, as long you have one of those devices in your household, you can set up free accounts for all of your other iOS devices too--as long as the devices are running iOS 4.2 or later.

You can verify the software version of your iOS device by launching its Settings app and navigating to General -> About and looking for the entry next to Version. If it doesn't say at least 4.2, you should update your device's software by hooking it up to iTunes and clicking the Check for Update button.