Dana-Farber's website is obviously a great wealth of information for anyone interested in learning more about Dana-Farber's past, present, and future.
Like the DFCI's, The Jimmy Fund's website can teach you a lot in a few clicks. There is plenty of text and multimedia for anyone interested in learning more.
The American Cancer Socitey is a similar group to the DFCI in some aspects. They provide many interesting facts and figures, and for anyone interested in cancer, they are an excellent source of information.
Another wealth of information is the National Cancer Institute. Again, anyone interested may visit their site here.