Sending signals to PC over wifi
For establishing a communication between a computer and an MCU I strongly suggest you to use Texas Instrument's CC3000 Wi-Fi chip with an Arduino (Easiest way to accomplish what you need). Adafruit and SparkFun introduced breakout* and shield** versions of the Wi-Fi chip. It is easy to use, just connect the wires and start communicating.

There is a strong library support of these products. Either of it can be found in relevant websites. You can send http requests to arduino or you can get http requests from arduino using these libraries. 

There are a lot of examples, sketches of this product. One of them is Wi-Fi weather station. Check the video, I believe this is what you want to accomplish.

*Adafruit's breakout
*SparkFun's breakout

**Adafruit's shield
**SparkFun's shield