sources for medieval sheet music?

I just acquired a reproduction Praetorius Scheitholt, with the intent to play 'period' music as part of the Society for Creative Anachronism (SCA).  I purchased a book from Folkcraft of medieval/renaissance/baroque music, but most of it is in DAD and some of that uses the 6 1/2 fret, which the scheitholt doesn't have.  I'd like to find sources of pre-1600 music in DAA tuning, planning on playing noter-style...any ideas where to look?

thanks!