This script will copy the files of the selected tracks or tracks of the selected playlist to a folder at a chosen location and include an M3U file referencing the copied files. (Optionally, create a .zip compressed copy of the folder.) Double-clicking the M3U file will load the files into a new iTunes playlist named for the M3U file.
OS X 10.6 or later only.
Here's an example of a folder the applet creates. The M3U file references the files that have been copied to the "media" sub-folder.