Taking from their site:
We have received hundreds of thousands of pages from corrupt banks, the US detainee system, the Iraq war, China, the UN and many others that we do not currently have the resources to release to a world audience. You can change that and by doing so, change the world. Even $10 will pay to put one of these reports into another ten thousand hands and $1000, a million.
We have raised just over $360,000 for this year (our yearly budget is around $600,000.).
The Sunshine Press (WikiLeaks) is an non-profit organization funded by human rights campaigners, investigative journalists, technologists and the general public. Through your support we have exposed significant injustice around the world— successfully fighting off over 100 legal attacks in the process. Although our work produces reforms daily and is the recipient of numerous prestigious awards, including the 2008 Index on Censorship-Economist Freedom of Expression Award as well as the 2009 Amnesty International New Media Award, these accolades do not pay the bills. Nor can we accept government or corporate funding and maintain our absolute integrity. It is your strong support alone that preserves our continued independence and strength.