Diamond Comics Dist. − The main wholesale comic book Distributor. Keep up with what's shipping when, news, Previews order book, etc. Good resource for dealers and fans.
CGC a.k.a. Certified Guaranty Company (formerly called Comics Guaranty Company) − The oldest and largest professional 3rd party comic book grading company, and really, the only legitimate one. (If you use anyone else just to save a few bucks and slabbing time, you need to do some research before you throw your money away. And no one's perfect of course.) Experienced graders certify a grade for your comics and comic magazines based on tight standards, check for restoration on older comics, and encase them in a nice hard plastic holder (commonly called "slabbing"), for varying fees. You can also search their Census database (you have to create a free account now to access it) to see how many of what issues have been graded in every grade. Their comic forums are a good resource for all kinds of knowledge, and to keep alerted to scammers and bad sellers, of which there are many, mostly on auctions.
Comic Book Database.com − (cbdb.com) − The most detailed comic book resource on the net! Use this free, interactive site to look up your favorite characters, artists, writers, or comic book series. The database currently comprises over 50,000 comic books and is growing daily. Many ways to search it too, so if you can't remember the exact issue number, but know the story title, or artist, writer etc., you can find the issue eventually, or simply find out all kinds of other info about the issue, like guest stars, creative talent etc.
Comic Book Resources − Comics News/Info/Chat/Store Links.
Conventionscene.com − Site lists major collectibles and genre conventions around the country. Also has links to creator's websites. List your show here! (Here's a tip too: many of the little banner ads there are out of date, but if you click on them you'll go to the show's home page, or page on that site, and usually that will have newer info.)
Gemstone Publishing − Publishers of the oldest comics price guide, "Overstreet's Comic Book Price Guide," and other collectibles guides for toys, rings and more.
Grand Comic Book Database (comics.org) − For all you people just searching for pics of comics, this is the place to go. With several hundred thousand covers scanned, and other info about issues, this site's goal is to index all comics made! (NOT the same site as the Comic Book Database listed above.)
Mike's Amazing World of Comics − An excellent database site, originally started for DC comics, but now includes most other major publishes. It has regular databases for covers, publishing chronology, and even to find reprints, and the Newsstand page lets you search for specific months/years to see all the comics that were published that month. Nice for buying presents from the month someone was born, or just start a collection based on particular years/months. Remember that the comic COVER date is different than the CALENDAR date the comic hit the stands, as most comics are cover dated well after the actual release date.
Scificonventions.com: Find a Sci-Fi Convention! − Just what it says. You can find conventions by month, theme, your state or region, plus info for first timers, a message board, and convention services.
Super Hero Universe − Comic Book News, Fan Art galleries, community boards, online comics, convention list, fan fiction, gallery of original characters, videos, wallpapers, shopping, links, and more.
Virtual Toy Chest − An online archive of toys from the '80s, '90s, and '00s. Check out dozens of toy lines and hundreds of pics!