Books:
o Michael Tenzer: “Gamelan Gong Kebyar : The Art of Twentieth-Century Balinese Music”  (Chicago Studies in Ethnomusicology)
More Information + Order: Here
o Sumarsam: “Gamelan : Cultural Interaction and Musical Development in Central Java” (Chicago Studies in Ethnomusicology)
More Information + Order: Here
o Michael B. Bakan: “Music of Death and New Creation : Experiences in the World of Balinese Gamelan Beleganjur”  
More Information + Order: Here
o Benjamin Brinner: “Knowing Music, Making Music : Javanese Gamelan and the Theory of Musical Competence and Interaction”
More Information + Order: Here
o Lisa Gold: “Music in Bali: Experiencing Music, Expressing Culture“ (Global Music Series)
More Information + Order: Here
o Andrew Toth: “Recordings of the Traditional Music of Bali and Lombok” (Society for Ethnomusicology. Special Series, No 4)
More Information + Order: Here
o Brita Renee Heimarck: “Balinese Discourses on Music and Modernization: Village Voices and Urban Views”  
More Information + Order: Here
o R. Anderson Sutton: “Traditions of Gamelan Music in Java:Musical Pluralism and Regional Identity”
More Information + Order: Here
o Marc Perlman: “Unplayed Melodies: Javanese Gamelan and the Genesis of Music Theory”
More Information + Order: Here

CDs:
http://www.technobeat.com/BOOKS/INDONESIA/Indonesia.html
 Technobeats” review of the 20 CDs “music of indonesia” with audio samples and purchase informations

...and millions of Gamelan CDs, too many to list here ;-)