Here's a link from the Library of Congress web page to a fragment of Thomas Jefferson's first draft of the Declaration of Independence.
We know bits of the Declaration of Independence-- 'We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness' but here's link to hearing the entire Declaration read by broadcasters of NPR's Morning Edition news program. They've been reading this for many years...it's very moving, and takes about nine minutes to listen to.
U.S. History.org is another good site for history related information and includes information of versions and revisions on the Declaration before the final draft.