True to its name, this site contains pretty much everything about Mr. William Shakespeare on the Internet—or at least everything worth reading. The site is a like an online course in Shakespearean and Renaissance theater, with extensive information on his biography and works. It also contains information on Shakespeare's dramatic contemporaries and literary criticism of the Bard.
The Folger Library in Washington, D.C. is the world's largest collection of Shakespeare materials (they also edit the Folger editions of Shakespeare's plays that you probably read at school). Their website is as useful and information-packed as the library itself, with resources for both the casual and serious Shakespeare scholar.
Shakespeare is an industry in Stratford-upon-Avon, the English town that proudly claims the Bard as its native son. This site has biographical information and photographs of Shakespeare sites. If you're interested in visiting Stratford or attending any of the plays frequently staged there, this is the site to visit.
The original Globe burned to the ground during a performance of Henry VIII in 1613. In 1997, a reconstruction of the Globe opened in London. The site is an important resource for Shakespeare and Renaissance studies, as well as a working theater that hosts frequent performances of Shakespeare's plays.
This excellent site pulls together the best Shakespeare sources on the Web. If you're studying a specific play, you can search by title to find just the information relevant to that one. It is especially good for finding information about past Shakespeare performances.
We here at Shmoop firmly support the idea that Shakespeare wrote Shakespeare's plays. This site mounts an impressive argument against the claims that someone else wrote some or all of Shakespeare's works.