I meant to do a ten things list on this topic but never got around to finishing it, and as the first item will go out of print soon, I thought I'd better post it now:
One of my favorite print magazines, Renaissance, is celebrating their 50th issue by featuring biography articles on the top 50 mystics, schemers, visionaries, scoundrels and bizarre men and women of the Middle Ages and Renaissance. This is a neat issue for anyone, especially if you write in or about those time periods.
For some insight on what it was like to live in Tudor-era England, Renaissance -- The Elizabethan World features an online and .pdf download of Life in Elizabethan England: A Compendium of Common Knowledge 1558-1603.
Daniel Traister has put together one of the most comprehensive links pages out there to online Renaissance Literature texts and studies, including a lot of Shakespeare-related links.
VoS, a website for humanities research, has pages of excellent links for Anglo-Saxon and Medieval Lit, Renaissance & 17th Century Lit and a lot more.