There is a plethora of sheet music for the classical guitar. Unfortunately, most of them are scans of the original manuscripts. Here you can download clean, accurate copies of those manuscripts.
Also, let me apologize. I just recently realized that you could not download the scores on MuseScore without a Pro account. I thought that if you have a free account you could sign in and download. This page is being fixed now to remedy that error. Stay tuned.