Interesting project! I think a good start could be a brief explanation of the musical climate of the late 50s. Maybe discuss the status of early rock icons (Elvis, Buddy Holly, Chuck Berry, Little Richard) and how early rock and roll was becoming more pop oriented, which can lead into the teen idols and pop groups (girl groups, Motown). From there, you could go into folk music, the british invasion, psychadelic rock, etc.
As for websites, I’m not sure I know too many. I took a history of rock and roll class a few years ago and the reading material was all online. I can link you to that http://www.eisel.us/rock/index.html . The 60s are discussed from Chapter 1-5 and are pretty short, easy chapters to read. This website http://www.spectropop.com/hmadanibrief.html has a very brief history as well. I hope those two can be of some help. Maybe a few followers may know of a few other sites to help you out?