Hi,
Assume this is an assignment ?
If you just search the web there are plenty of such projects for you to copy - here is just one I found, the sensor is, I believe, the equivalent of a us100 and the code will need a little modification to flash a led.
As you can see you will need some software to compile the various program codes you could use, and some means to program the Pic chip ?
Do you have to use a particular compiler or have got access to a programmer in your college ?