Apple posted some interesting sample code called TimelineToTC that takes a Sequence XML file and returns a basic edl file of the selected attributes. Not very full featured, as is typical of Apple sample code, but is a good starting place for someone looking to do conversion work or a more full featured edl. Worth a look especially for a nicely packaged function/method called FormatTimecode which takes a frame count and returns a formatted time code string accounting for drop and non-drop frame sequences. handy.