Having to do with Written Music

ANA’s collection: Written music and Allspel list
Henrik Norbeck: Swedish written music
Scandinavian Folk Dance Music, JC’s repository of ABC & GIF files
Folkets Hus Spillefolk: Massive tune collection for Scandinavia
Blue Rose Music: A wonderful tune compilation organized by location

ABC Files

The ABC homepage: Write music with normal text files!
ABCMUS: a $10 shareware ABC program
A Tunefinder: Search the web for particular ABC tunes
Folkwiki: A growing collection of Swedish Folk Tunes in ABC and MIDI

Information on temperments and tuning:

Terry Blackburn’s guide to alternate temperments

Learning Tools

Amazing Slow Downer: Slow down CDs without changing the pitch.