Other
Lute Harpsichord: A Forgotten Instrument
Interesting website on the lute-harpsichord, which is called "one of Bach's favorite keyboard instruments." Provides an in-depth history of this "forgotten instrument" and the ordinary lute.
Other
Guitar and Lute
Great website for information on guitars, lutes, and other musical instruments. A lot of free items like music, tablature, and art. Useful to those studying music, including beginners.
Dartmouth College
Dartmouth College: Lutes, Old and New
A great website for a wide range of information about the lute. Includes pictures, questions and answers about the instrument, and even a directory of lute makers. Very useful for those interested in buying a lute.