Here are some helpful links for collaborative music:
MTNA's webpage for the Year of Collaborative Music is http://www.mtna.org/Default.aspx?tabid=677.
ISB member Paul Nemeth has created a massive database of chamber music works with bass. If you're looking for repertoire ideas go to http://www.paulnemeth.com/basschamber.htm.
Double Bass.org also has a chamber music listing at http://www.double-bass.org/music.html.
ISB board member and chair of its YCM initiative Jeremy Kurtz will be posting articles relating to the Year of Collaborative Music and chamber music with bass on his website throughout the year at http://www.jeremykurtz.com/writing.html.
The Amateur Classical Musicans Association has relevant information for finding other musicians who are looking for chamber groups at http://www.nycclassical.com/.
The Chamber Music Network also has helpful listings for finding other musicians at http://www.acmp.net/index.php.