MiddleClickApp is described as 'MiddleClick is a free app with the only purpose of enable the middle click with magic mouse'. There are four alternatives to MiddleClickApp for Mac and Linux. The best alternative is BetterTouchTool. It's not free, so if you're looking for a free alternative, you could try touchegg. Other great apps like MiddleClickApp are Jitouch (Paid) and Multitouch (Paid).
BetterTouchTool is a great, feature packed app that allows you to configure many gestures for your Magic Mouse (1 & 2), Macbook Trackpad and Magic Trackpad (1 & 2) and also Mouse Gestures for normal mice.
Touchégg initially going to be designed to provide Egg Window Manager window management through gestures, but eventually I decided to extend this funcionality, so Touchégg is compatible with any window manager, and providing more options.