We are in the business of building iPhone apps. So we tend to be very interested when it comes to the most popular/most downloaded iPhone apps.

Here is a list of 5 of the iPhone apps that dominated the apps marketplace this year:

• SPY Mouse: If it’s not Angry Birds, it’s mice. The game revolves around Agent Squeak, a spy mouse, who is a super-secret operative serving the needs of mice everywhere. Danger. Intrigue. Cheese. It doesn’t get better than this.

• Plants vs. Zombies: What is it about zombies that drives all geeks wild? This game has won more than 20 Game of the Year awards. The premise is simple…you take on a mob of zombies who are about to invade your home.

• Fruit Ninja: If fruit carnage is your thing, then this game is for you. Join the million of other players who have already downloaded this app to join the world of ultimate fruit destruction.

• MadPad – Remix Your Life: This popular music app lets you record everyday sights and sounds into the ultimate music instrument. You just aim, shoot, record and share music videos. Easy. Fun. Awesome.

• WhatsApp Messenger: We are all pretty much addicted to this iPhone app. WhatsApp Messenger is a cross-platform smartphone messenger currently available for iPhone, Android, BlackBerry and Nokia phones. No more spending money on smses. Plus you get to chat to your friends overseas. Best app ever.