This predominatly French site has a wealth of information although some of it is quite dated for example the following two Books and there is quality information to read here.
by Claude Rivière Ithaca. Cornell University Press. 1968. 260 p.
A former Serf Village in the Republic of Guinea
by William Derman University of California Press. 1968. 280 p.
has a very kule overview of the Baga people and for the history of Guinea you may check Festival de Guinée.
These folks have some other kule art to look at, in addition to the great description and pictures of the Nimba mask the Baga people are famous for.
has a short blurb on Guinea and a nice map.
and at the Yahoo Store there are some WAV files of four tracks on the CD "Baga Guine" by a 16 piece female group of Baga ladies that were discovered in the National Percussion Competition in Guinea in 1989. The group has made it a point of honor to keep Baga traditional dances, songs and rhythms alive. Their songs evoke the great moments in the life of Baga women.