How delete friends?

Does anyone know how to delete friends from your profile...there is this one guy who doesn't got to Stetson who is my friend and I don't know how he got on there. Plus, he posts all of the time and is taking up all of my space on my friends entries.

For Dr. O'Neill: Do our posts on our personal journals effect our grade as well as replying to your questions and others in the community? I guess I am just a little shady on how this whole grading process works.