A few examples:

Good Search

Design 21 - Social Design Network

Creativity Pool - Not exculsively for good

Sharing is Caring - this one starts to address the issue of capitalistic drive versus opportunity cost of trying to get paid

SSIR - you're not the only smarty-pants-for-good out there ;-)

If you've decided to forge ahead, these resources might help you:

InventRight

PartnerUp