Apparently I came off as pompous by mentioning the philosphy minor, and for that I apologize.
However, to say there is anything different about unethical behavior and immoral behavior is merely arguing semantics, particularly in this case when the exact defenition doesn't even really matter.
Even if it were, "unethical" is far more accurate than "immoral." The latter infers a knowledge of wrong-doing, and I hardly think anyone who steals a pencil from work is convinced they're going to hell for doing so. On the other hand (and yes, I know this is going to be a very narrow definition), unethical more often implies breaking some kind of moral guideline.