Line with one set endpoint, and one cursor-following endpoint

Hi, I’m kind of new to Flash (I’ve used it a fair amount, but I haven’t really delved into AS too much) and I’m trying to learn how to do something:

I want to have a straight line, with one end at a set point, and the other end following the mouse cursor around, so that no matter where in the movie my mouse is, the line connects it to a set point. Any ideas how I could do this? I don’t shy away from taking the time to learn something, so if anybody wants to point me in the direction of a/some tutorial(s) that might help me understand how to figure this out, I would appreciate that as well! Thanks.