Channel Four has produced an animation on understanding clinical trials called "How do drug trials work?"
Take a look - it's only 4 minutes long and explains in simple terms all the phases a drug goes through in development. It also includes a quick explanation of who is involved in funding research:
http://foodhospital.channel4.com/the-truth-about/videos/the-truth-about/how-do-drug-trials-work/
For anyone who'd like a more detailed explanation of clinical trials, the Parliamentary Office of Science and Technology (POST) has published a postnote which summarises what clinical trials are and why we do them:
http://www.parliament.uk/pagefiles/504/postpn390_Clinical-Trials.pdf