http://www.a-cappella.com/ - Sheet music, CDs and other stuff!

 

http://www.collegiate-acappella.com/ - A directory of college a cappella groups around the country!

 

http://www.casa.org/ - Contemporary A cappella Society, has articles and information about a cappella.

 

http://www.sa.rochester.edu/ramblers/ - Midnight Ramblers, one of University of Rochester's male a cappella groups

 

http://www.sa.rochester.edu/vocalpt/ - Vocal Point, University of Rochester's female a cappella group

 

http://www.hyannissound.com/ - A group made up of 10 guys from around the country that perform for 3 months over the summer. 

 

http://www.m-pact.com/ - M-Pact is a professional a cappella group from LA, is a mix of R&B, Jazz, Pop/Rock. 

 

http://www.eclipsesingers.com/ - Eclipse is a professional group from Utah.  Vocal Infusion has sung some of their arrangements

 

http://www.slapdashgraduate.com/ - A up and coming professional a cappella group from Boston!