I found this site whilst looking for something else (happens tp me a lot)

It has a great quantity of Lute music in Tablature as .pdf and .eps formats also MIDI format which will play in Widows Media player or could be imported to notation software for conversion to notes on staves. The files are all downloadable for free and cover works by most composers from Renaisance and baroque periods.

The page linked below has further links to things about lutes, theorbo, and other contemporary string instruments, even some new and second hand sales. (I have also posted this in the Love of Baroque forum)