LOUNGE DELUXE  An app that saves playlists was exactly what I was looking for, and indeed iTunes Song List does save playlists and you can even choose from several file formats.

But after a playlist has been saved, iTunes Song List makes iTunes quit and that is very annoying. I'm using the latest version of iTunes (7.6.2).   
(Version 1.2)

DB  thank you for sharing this. I've been doing this by hand with TextWrangler and before that BBEdit Lite for so long now that it's become second nature to me ... it will be interesting to go with an easier system.  
(Version 1.0)

ROBK  The program seems to run just fine. But it keeps asking you questions like which font and size you want before the list is finished.

Since it just dumps the information into a TextEdit file, I would let the user set these options using Textedit. Or add an options button where you can set the font and size permanently.

Pity it is not open source so one could customize this script as he or she would like.  
(Version 1.0)