I came across this blog a few days ago, when searching for information on a book about Plath, Eye Rhymes: Sylvia Plath's Art of the Visual.
I've been reading her work for years now, and have grabbed almost everything that has been written about and by her.
I can't believe the amount of information on (the aptly named) Sylvia Plath Info blog! Any bit of news that comes out concerning Plath, will be found on SPI.
The author of the blog, Peter K. Steinberg, is well-versed in everything Plath, and has written a book on the subject.