Studying brewing has opened up the world of beer to me in new ways, and I've begun to discover that there's a lot more to it than I ever imagined. There's a history that goes back to the earliest human civilizations, and a bewildering array of styles far beyond the light pilsners I grew up having around in rural Missouri. In order to get up to speed on these styles I've done a lot of reading, and the best resource in print I've found is The Beer Bible (Second Edition), but Jeff Alworth. This guide is the sort of book that you don't read cover-to-cover (although I suppose you could), but rather can open up pretty much anywhere and read.
Another option, if you have the patience to sit and watch a video that goes over an hour, Master Cicerone Pat Fahey has produced an excellent intro to every beer style. You can check that out below. And, happy drinking!