On 12 February 2009, 100+ cities around the world will be hosting
Twestivals bringing together local Twitter communities for an evening
of fun as well as raising money and awareness for Charity: water. Twestival.fm is a global online music project in association with Twestival aiming to raise an additional $20,000 for charity.

They're now looking for artists, musicians and labels using Twitter
who would like to give something back to the community and donate a
track. You’ll be helping raise money for a good cause and promoting
your music to an audience of tens of thousands. They also expect
international press attention and plenty of buzz in the Twitterverse.

All donated tracks will be made available to stream and download for free via the Twestival.fm player (powered by SoundCloud ).
The player will be available to the general public from 5th to 19th
February. Visitors to the Twestival.fm site are asked to leave a
voluntary donation or ‘tip’ (using Tipjoy) in a Radiohead-style ‘pay what you want’ manner. All tips will be given in full to Charity:Water and the most generous tippers listed on the site.

get more info about this nice project on the Twestival.fm and/or the Twestival homepage.