Coralpad

Coralpad lets you use your mobile phone as X-BOX 360 Controller for your computer. Coralpad will be helpful for a lot of games. Its features :

Fully customizable layout (Size, positioning, color, and mapping), design your own layout!
Layout Manager, quickly switch into different layout that benefits you the most!
Represent analog input into slider for more precise control
Represent analog input into thumbpad.
Map analog input into device's motion sensor
High refresh rates (100Hz)
Sticky control enables you to leave slider, thumbpad, and button at its current position after lifting your finger, freeing your hands to focus on other aspect of the game
Easy to set up and use
Wide compatibility with games
Source