Check out this website http://forgood.yahoo.com

Hack for Good

Any hack or mashup that could better the world and allow more social awareness

Examples:

How green is this website Hack
Custom Searchmonkey module for nonprofits
Green calculator, (measures carbon footprint)
Mashups that can bring the community together for a cause
disaster relief tools
help people connect with various local charities
any  tools that bring people together for social causes
get amber alerts on your phone
online version of the emergency broadcast system