I have just had an email from the webmaster of Charity-Ware.org an index of software for which the developer asks that money be donated to charity. Did you know that Vim is charity-ware ? Neither did I. Of course, that is part of the problem - and its nice to see an organisation trying to do something about it.
Of course, you don't need to have software in return for giving money to charities like Shelter - just donate something! :-)