Computer music & Music Information Retrieval
International Computer Music Association (ICMA)
International Conference on New Interfaces for Musical Expression (NIME)
music-ir.org: Virtual home of MIR research
International Conference on Music Information Retrieval (ISMIR)
Cory McKay's great resource list
Music Machinery: Paul Lamere's fantastic blog

organizations I've worked with
Smule is sonic media
Microsoft Research - VIBE group
Princeton Graduate Engineering Council
Princeton Computer Science graduate committee
Post-Graduate Students' Society of McGill University
Music Graduate Students' Society of McGill University
Sun Microsystems - Burlington MA Research Labs
Alpha Omega Epsilon: Social and Professional Sorority for Women in Science and Engineering
ACM-W: ACM's Committee on Women and Computing
Tau Beta Pi: Engineering Honor Society
Central Ohio Flute Association (COFA)

mailing lists
Systers: online community for women in computing
music-ir: Music information retrieval
freecycle: local communities for recycling your old stuff

Organizations/Initiatives I support
Amnesty International
Human Rights Campaign
Immigration Equality
Uniting American Families Act: so I can sponsor my wife for immigration
Computer Professionals for Social Responsibility

My other favorites
Evernote: free software for taking and organizing notes
cheese.com
ubuntu: linux for human beings
slayage: online international journal of buffy studies
pandora: free, personalized internet radio
last.fm: social music recommendation powerhouse
goodguide.com: learn what's in the products you use
vegweb: vegetarian recipe-sharing community
slate: a flavorful take on current events
NY Times: Be informed! Subscribe to the free email version