Almost identical to loops in most other languages. There are various types.
A 'while' loop (the hint's in the name): while (conditions) { actions }
E.g.
var i:uint = 0; while (i < 10){ trace("Loop Number "+i); i++; }
Google is your friend in this case, and there are some very simple and thorough tutorials out there to get you started. Try this republic of code tutorial to start with.
