The Lyme Research Alliance is a useful resource. Sign up for their newsletter.
The Wikipedia article on Lyme disease is comprehensive and informative.
Here's a great piece on the history of the "Lyme Wars" from the Boston Globe.
Mary Beth Pfeiffer was nominated for a Pulitzer Prize for her series on Lyme in the Poughkeepsie Journal. Here's her take on the Lyme Wars.
Another prominent group: LymeDisease.org.