Other useful Swamp Thing related resources on the internet.

General Information
Wikipedia provides a general overview of the character and the publication history of the comic. There are also pages for each of the films and the television series.
DC Comics are the publishers of Swamp Thing and there is a character page with news of recent and forthcoming comic appearances.
– There is also a character page at Comic Vine, which has some information about Swamp Thing’s appearances across all media, as well as regularly updated news and a link to relevant forum posts.

Greg Plantamura’s Annotations for Swamp Thing provides incredibly detailed annotations of the issues that comprise the Alan Moore and Rick Vietch runs, including details on the cancelled ‘Jesus‘ issue.
Roots Of The Swamp Thing provides, amongst other things, a very long list of comic and magazine appearances.  There are blog posts and partial scans of many of these, as well as information about other Swampy collectables. It is updated frequently and run by John Boylan – a huge Swampy fan and current Guinness World Record holder for largest collection of Swamp Thing memorabilia.
The Parliament Podcast features discussion about current and past issues of Swamp Thing and related collectables.
Swamp Thing 101 is a blog that features news and reviews.
Avatar of The Green is another blog that features reviews and criticism.

Film & TV
IMDb provides useful overviews of the 1982 film, the sequel, and the live-action television series.
Arcane Knowledge includes synopses of the films and cartoon, but focussed primarily on the 1990 television series, with a detailed episode guide and biographies of cast and crew. There is also a document created by series writer Tom Greene detailing some of his plans for the series and characters, but I have had trouble accessing the file properly.
CultTVman’s Swamp Thing Page has synopsis and production information for television episodes, and a few pages about the films and cartoon.

For Educators
SANE journal “publishes research and practitioner-based articles covering all intersections of comics and education”, including rationales for the teaching of specific titles.  Vol.1, No.2 is devoted to the works of Alan Moore, with various references to Swamp Thing and a rationale for teaching #20-27 to high school English classes.

Creator Sites
Series One
Len Wein [co-creator, writer] : twitter
Bernie Wrightson [co-creator, artist] : website / twitter
Nestor Redondo [artist] : fansite

Series Two
Thomas Yeates [artist] : website
Tom Mandrake [artist] : website / twitter
Stephen Bissette [artist] : website / twitter
Alan Moore [writer] : facebook / fansite
Shawn McManus [artist] : website
Alfredo Alcala [artist] : fansite
Rick Veitch [artist, writer] : website
Ron Randall [artist] : website
Neil Gaiman [writer] : website
Mike Hoffman [artist] : website
Nancy Collins [writer] : website / twitter
John B. Higgins [cover artist] : website
Ian Miller [cover artist] : website
Charles Vess [cover artist] : website
Phil Hester [artist] : twitter
John Mueller [cover artist] : instagramfacebook
Mark Millar [writer] : website / twitter

Series Three
Roger Petersen [artist] : website

Series Four
Andy Diggle [writer] : website / twitter
Joshua Dysart [writer] : website / twitter
Enrique Breccia [artist] : website

Series Five
Scott Snyder [writer] : twitter
Charles Soule [writer] : website / twitter
Nathan Fairbairn [cover artist] : website / twitter
Yanick Paquette [artist] : twitter
Marco Rudy [artist] : twitter
Jose Ángel Cano López [artist] : website

Series Seven
Ram V [writer] : website / twitter