A new project came out on kickstarter.com that is based on Arduino called Ard-Vark. It is ready to go wifi controlled solution, in a nice case. You can plug in sensors for inputs and/or servos or DC motors for outputs and control them easily using a mobile app for iPhone or iPad or Android device. With the Ard-Vark you don't have buy an Arduino then a shield for wifi then get the software loaded and then write your own software. You just set it up on your network and then connect to your smart phone and control it easily. You can also control it from a web site if you want.
Link to the project on kickstarter is http://www.kickstarter.com/projects/694850905/the-ard-vark