Apple has an app that allows you to invite friends or family to monitor. At the same time, you can be monitored if you choose. The app is called Find My Friends.
Apple describes the app as follows:
Find My Friends allows you to easily locate your friends and family from your iPhone, iPad, or iPod touch. Install this free app on your device running iOS 5 or later and sign in with the Apple ID you use with iCloud. Adding a friend is easy — just send a request to see their location. Once your friend accepts using the Find My Friends app on their device, you will be able to see their location. And friends can request to see your location the same way.
If you prefer, you can also choose to share your location with a group of friends for a limited time. Use Find My Friends to keep track of your traveling companions when you’re on vacation. Or to see if the kids are home from school. Or to meet up with friends for dinner.
If you’re running iOS 6, you can also set up location-based alerts — to notify you when your kids leave school or a family member arrives home safely — or have Find My Friends notify others about your location.
You need to be running iOS5 or later, have an iCloud account and internet access. If you want to keep up with kids, family and friends who have or are using an iOS device, this app is the way to go. If you are being followed, you can, if you want, turn off the feature so you can’t be monitored.
To turn off those who are following you, click on “me” and slide on “Hide from Followers.”