Animate a line being drawn along a motion guide layer

[anime280]

Hi, I have a question and I'd really appreciate your help. My question is how can I animate a line being drawn along a motion guide layer, that's where the line follows the guide from the start point to the end point, i.e. the line draws itself, I know how to do it using masks but it would be very hard if the line has lots of twists and intersections. can someone help me please?, and one more thing I'm a newbe to ActionScripts so please be more detailed, or send me an FLA as an example, thank you.