Halloween is almost here, which means more scary movies, haunted houses, and candy-related indigestion. It also means a lot of fear and fun. apps for your iPhone or iPod Touch. Whether you want to play a scary game, manipulate a photo to trick your friends, or choose a great costume, the following apps are sure to make your Halloween memorable. Read on for all the ghosts, zombies, aliens, and heartthrob vampires you can handle.

Dark camera: When it comes to scary photo medicine apps, Camera Obscura is the original, and it’s still the best. The premise is simple: just take a photo from within the app or select a photo from the iPhone’s photo library and choose your look. Then simply choose where it goes on the image, how translucent it should be, and other details, then save it, send it, and scare your friends. Camera Obscura has a cool sepia-toned interface and lots of fun features. It will still be fun even after Halloween is over.

Plants vs Zombies: The success of Plants vs. Zombies is no secret: this game is consistently among the top sellers on the App Store and has won over 20 Game of the Year awards. Now that Halloween is coming, it’s the best time to try this scary and addictive game if you haven’t had the pleasure yet. Plants vs Zombies is a kind of puzzle game and a kind of action game. The goal is to control an army of plants, using their special plant powers, to fight off an onslaught of zombies. It is foolish? Very. It is also very difficult to leave.

Search: Look-Up is hopefully the closest any of us will ever get to witnessing an alien invasion. A winning combination of game and augmented reality app, Look-Up will turn the world around you into an interactive alien-fighting experience that will keep you on the edge of your seat. Simply look through the iPhone’s built-in camera and Look-Up will overlay the image with a variety of UFOs that you must destroy to earn points and advance to the next level. More than just a trick, this is a very fun game in its own right.

The Twilight saga: The Movie Game: Halloween is the time of year when the scariest creatures of all come out of hiding and show their faces: Twilight fans. Jokes aside, vampires and Halloween go together like candy and regret. The official Twilight iPhone app is sure to please any fan of the popular series: players can solve puzzles, answer Twilight trivia, and even share scores with other “fans.” Best of all, additional content for New Moon and Eclipse can be purchased from within the app.

Halloween Costume Generator: When it comes to finding Halloween costume ideas, kids have it easy: Spiderman and Disney princesses never go out of style. Adults, on the other hand, need to answer questions about whether or not to go with a topical reference, whether to make the costume sexy or conservative, and of course how much to spend and whether the costume will be comfortable enough. Halloween Costume Generator is an iPhone app that will help you navigate these troubled waters in a fun and irreverent way. Users can enter search criteria and filter results by mood, occasion, gender, and more. This app is as fun and hilarious as it is downright useful.