This Halloween, a crop of geo-location apps can help parents keep tabs on their kids as they roam the neighborhood in search of tricks and treats.

While these apps are certainly no replacement for an attentive - and physically present - parent, they can help provide ease of mind for those with trick-or-treaters old enough to venture out on their own.

An app for Android smart phones called Trick or Tracker, when installed on both a parent's and teen's smart phone, can keep the parent updated on the teen's location.

The parent selects an interval of time - say, 15 minutes - and receives a text message as each interval passes with the kid's location.

Parents can also set up a geo-fence and get an alert if the phone leaves a defined perimeter.

The information will, of course, be accurate only as long as the smart phone remains at the ghost or goblin's side. A phone stashed in a neighbor's mailbox will broadcast that same location for as long as it sits there.

The Trick or Tracker app costs $4.99 for each download and can be downloaded at www.trickortracker.com.

There are also some everyday apps that perform some of the same tasks and are free.

Google Latitude is a free app and service that allows users to sign up to receive the real-time locations of friends and family members.

Each party has to approve sharing his or her location with the other, a process similar to friending on any other social network.

Google Latitude has apps for almost any platform, including Android, iOS, Windows phones and the BlackBerry. A connection's location can also be tracked on the Web, showing a map with a moving marker for the traveling child.

Apple, too, has a location tool called Find My Friends that is compatible with devices running iOS 5 and works similarly to Google Latitude.

These free apps, though, will allow a tech-savvy teenager to turn off the location broadcasting. And make sure those smartphones are charged up before an evening out. Apps that use a phone's GPS system constantly in the background are notorious battery hogs.

MORE HALLOWEEN APPS

• The festive folks behind the popular Angry Birds game hardly let a major holiday go by without an update to the Angry Birds Seasons app.

This Halloween, gamers get 30 new levels and a brand new orange bird to combat those pesky pigs.

The game is updated a few times a year for free to mark occasions such as Christmas and Valentine's Day.

The Seasons app is available for Android (free), the iPhone and iPod Touch ($.99) and the iPad ($1.99).

• Another now-classic mobile game, Plants vs. Zombies, is a great haunted distraction for this week.

Players fight to keep zombies from coming inside their house. (If the zombies come inside they'll eat your brains and it'll be game over.)

Players fight back by planting menacing plants in their front lawn that keep the zombies at bay.

It sounds wacky, but it's one of the smartest games out there, gradually building by adding new weapons as the gamer learns the ropes.

Plants vs. Zombies is available on Android, iOS, Mac, PC and also online.

• If you're looking to create a virtual pack of the undead yourself, check out the fun app Make a Zombie, which is a free app for iOS devices.

Users can choose between near-limitless options of hair, blood-spattered clothing, empty eyes and missing appendages and then download the image of the surprisingly cute cartoon zombie to their phone.

It's a great way to get a fresh Facebook photo for the holiday.

• And for those who need a way to scare their friends, check out the iPhone app Fright Factory ($1.99).

The app's scary stunt is hiding inside a series of optical illusions that asks the phone's holder to stare intently at the screen. During the third illusion, a zombie pops up and screams, which is sure to spook anyone paying rapt attention to the illusion.

Just make sure your friends aren't so spooked that they drop the $200 smartphone to the floor.