The link you provided is: www.ismlp.comHowever, that seems to be a cyber-squatter website. You couldn't possibly have ment: www.imslp.comCould you?
Your link doesn't work right either. Way to phail MelloKira
Nod, this is the most comprehensive database of PD music in existence. Much of this music has not even been in print within our own lifetimes, and may have otherwise been lost. Finale can read music score scans, and then convert to midi, but you miss a lot of the nuances implied by a composer or editor when imported as a midi instead of as printed page.