1. Dread Central
A huge megasite for horror news headlines. Also available here: podcasts, reviews, interviews, and video.
2. First Fright
This horror news site is updated very frequently, so it should be one of your first stops in the morning when you're looking for horror genre updates.
3. Hammer Horror Fans
One of the few Yahoo! groups I've seen lately that is still on topic and still carefully moderated so there isn't any spam! Fans of the Hammer Films and related directors, actors, writers, etc. use this group to connect.
4. Horror Movies
Probably the best LJ community for the horror genre. Lots of posts, not a lot of apparent 13 year olds, and not much Twilight spam. Seems to be well moderated, and with 2000 members to contribute, you'll likely find a lot here of interest.
5. Horror Movie Fans
The two best things here are the news blog and the active message boards. Sadly, the other portions of the site aren't currently working.
6. Horror Society
A fabulous high-quality website focusing on independent horror. Besides the usual news, reviews, and interviews, they'll keep you updated on horror festivals and conventions. They also have a thriving forum and community. Well worth your time to visit this site if you haven't in a while.
7. House of Horrors
One of the few horror movie genre sites that hasn't given up the website format for a blog. This one has updated news and horror movie reviews, plus back archives of interviews, info on directors and actors, and other valuable resources.
8. Icons of Fright
Exclusive interviews with horror actors, directors, and writers. Plus convention reports and up-to-date news.
9. Pit of Horror
This cool horror website has been around since 1998! I'm delighted to find it still going strong.
10. Retro Slashers
"Unearthing forgotten horror." News, reviews, retrospectives and interviews.
11. Terror Trap
This website is a museum for horror movies made between 1925 and 1987. Categories include Italian horror, the undead, ghosts and monsters, slashers, and the supernatural 70's.
12. Universal Monster Army
A forum/community based around classic monster movies. You can register here to participate in the community, but are welcome to browse as a guest.
13. Upcoming Horror Movies
A great way to stay caught up with news and info on horror films coming out in theaters (and on DVD/Blu-Ray) in the next couple months. There's a gallery, message board, and a database of upcoming horror movies in development.