This poster presents a Brazilian popular music oriented digital library proposal conceived for a virtual community of people interested in acquiring knowledge about Brazilian popular music harmony, particularly in choro. This Brazilian musical style is a complex popular music form based on improvisation, although it contains classical music elements such as the counterpoint. We are proposing two ways of accessing the music virtual library content: a guided navigation mode, in which users interact with a cooperative Web-based learning system; and a free navigation mode, in which users can make their own queries, both through browsers or client applications.