rs1485,
The source is included with the Arduino distribution.
I believe it's all there, if you look for it.
You'll want to read the chip's datasheet as well.
Does the course project require that you not use Arduino's libraries? I ask because I wonder 'what could possibly be the point of all of this'?
If the use of the Arduino libraries is forbidden, then is is a great exercise. I just hope that it's not due tomorrow.
-Chris