"Shakespeare's Life and Times"
This website contains a lot of useful information on Shakespeare. The history section is especially interesting and broad. It includes information ranging from the monarchs during Shakespeare's time to crime and law in Elizabethan England. Apart from history, the website also includes sections on society, drama, and literature.
This website is an excellent resource for supplementary readings on nearly every play. The essays for each play are numerous and cover an array of topics. The website also has an "analysis" section, but only a few plays are listed.