The BBC recently did an on-air documentary about William Wilberforce, replete with dramatizations and interviews. You can listen to it here or read an outline of the program.
You can also read or listen to John Piper's biographical sketch of Wilberforce's life. Piper's book, as well as a downloadable audio version, is also available.
Eric Metaxas is the author of the official biography, Amazing Grace, being tied to the movie. He recently did a print interview with National Review. National Review also recently conducted a short online symposium, asking some statesmen (Sam Brownback, Tom Coburn, Chuck Colson, Richard Land, Mark Rodgers, Douglas Minson, Mark Souder) what makes Wilberforce inspiring.
You can also check out the works of Kevin Belmonte, the director of The Wilberforce Project at Gordon College. He's the author of the major biography, William Wilberforce: A Hero for Humanity.
If you want to read Wilberforce himself, see his A Practical View of Christianity, or 365 Days With Wilberforce: A Collection of Daily Readings from the Writings of William Wilberforce.
Also, see Focus on the Family's Radio Theatre has produced a five-hour dramatized audio production available in a five-CD set: Amazing Grace: The Inspirational Stories of William Wilberforce, John Newton, and Olaudah Equiano.