Reading serial port with c programming

Here is the deal!

I need to read (read only, not write) the data from the serial usb port using a c program. I have no idea how to do this but I would like it to be vary simple. Get the data... store it in a variable so I can play with the content and do this over and over again.

Can anyone help me out with this.

Go here & scroll down to Serial

http://arduino.cc/playground/Main/InterfacingWithHardware#Input