Spanning 43 years, six television series, and eleven movies, the Star Trek universe can be daunting. Here's a guide to the best online resources to get you caught up before you see the movie.
Official Sources
We'd be remiss if we didn't start with the official Star Trek website, although it's hardly the best resource out there. Parts of the site seem completely deactivated, with even their news page barely updated past 2007 (and call me crazy, but I'd say there's some Star Trek news to report at the moment). Still, CBS has dozens of Original Series episodes available online, so Star Trek's official web presence isn't a complete washout. That said, it's hardly surprising that if you really want to learn about Star Trek, you've got to go to the fans.
General Reference
Wikipedia has a pretty decent Star Trek Portal that is a great starting point to explore their articles on the franchise. But even Wikipedia can't hold a candle to Memory Alpha, the dedicated online encyclopedia for all things Trek. The existence of Memory Alpha makes this list about a tenth as long as it would have been even a few years ago, as it covers pretty much every conceivable topic you could possibly imagine. If you want to jump into the deep end of the Star Trek universe, a couple hours spent at Memory Alpha is pretty much the best way to start. If that's just not nerdy enough for you, there's always Memory Beta, which exclusively covers all the stuff that doesn't even officially exist in the Star Trek universe, like all the novels and comic books that have been written over the years.
Beginner's Guide
Of course, all that information all in one place can get a little daunting, so you might want to step back for a refresher course. Again, it's got to be said that Star Trek's Wikipedia page is a pretty good primer, tracing the show's history from Gene Roddenberry's initial ideas for the show to the new movie. If you can get past the early 2000's design, The Omega Quadrant is also a good place to go for a stripped down beginner's guide to the show. It carefully works through both the factual and fictional history of Star Trek, assuming no prior knowledge and taking the time to answer all the questions that tend to confuse non-fans (like the legendary issue of what's the difference between a Trekkie and a Trekker).
Episode Guides and Reviews
The official site, Memory Alpha, and Wikipedia all have fairly extensive episode guides, although TrekGuide is probably the best website specifically devoted to the topic, providing helpful charts that for instance list which aliens appear in which episodes. If you're looking for episode reviews, Jammer's Reviews might be the gold standard, covering everything except the Animated Series (he also looks at the new Battlestar Galactica and Gene Roddenberry's other science fiction show, Andromeda). Tim Lynch's Reviews also have their charms, but he only covers parts of the 24th century shows (TNG, DS9, and Voyager), and none of The Original Series or Enterprise. The always excellent AV Club is currently working through The Original Series, with weekly posts each reviewing two episodes (they're just starting up on season 2).
Military Science and Technology
One topics on which Memory Alpha hasn't made other sites obsolete is tech specs for the franchise's starships. Star Trek Intelligence is written as though it's, well, an intelligence report prepared for the Federation, compiling all known information about every ship from Xindi Reptilian Cruisers to Kazon Torpedo Ships and quite literally everything in between. The Starship Schematic Database focuses more on visual records of the ships. Either way, half an hour spent at one of these sites will get you ready for war, 23rd century style.
Toys and Collectibles
When just watching Star Trek isn't enough, it's time to stock up on some toys, and there are certainly no shortage of options. Both The Star Trek Toy Reference Center and Star Trek Toys Online list pretty much every toy ever made from the sixties onward. Toys Online wins based on aesthetics, but the Reference Center arguably has a more complete visual record, so I suppose it depends on what you care about looking at. Still, Toys Online does have eBay links beneath all of its pages, so it's the better option when you're actually ready to start spending.
Costumes
Unfortunately, there really isn't a comprehensive guide to the world of Star Trek cosplay, but at least Star Trek Costumes offers a comprehensive catalog of Federation uniforms from every era. If you've ever wondered how diehard Trek fans manage to pull off authentic Klingon costumes, here's the complete seven part process for making your very own Klingon forehead.
Conventions and Online Communities
Looking to meet up with your fellow fans? Though just about any science fiction convention is pretty much guaranteed to have a Star Trek presence, the franchise's very own convention is Star Trek Las Vegas, which will be held in August with William Shatner and Leonard Nimoy already announced as attending. There are also no end of online communities for Star Trek fans to get together, including United Federation of Trek,
Trek Web, and Starfleet. Finally, though it hasn't launched yet, the massively multiplayer role-playing game Star Trek Online has already built a strong community as fans wait for the opportunity to explore the game's 25th century setting.
Fan Fiction
Though it's not for the faint of heart, Star Trek fan fiction offers the adventurous fan an opportunity to explore the universe in ways the official version hasn't. Star Trek Fan Fiction and Orion Press are two of the best, but I'll leave it to you to locate some of the worst (they're certainly not hard to find).
Star Trek is also notable for not just prose fan fiction but also a huge amount of fan films, some of which have taken the form of full-fledged amateur TV series. Star Trek: Phase II, formerly The New Voyages, started as an attempt to complete the five-year mission of The Original Series, and has since morphed into a more open-ended continuation of Gene Roddenberry's original ideas. Although the show features the original characters played by new actors, both George Takei and Walter Koenig have appeared to reprise their roles as Sulu and Checkov, and Roddenberry's son serves as a consulting producer.
Equally impressive is Star Trek: Hidden Frontier, which has made fifty full-length episodes depicting the voyages of the USS Excelsior in the Next Generation era. Current Star Trek rights owners CBS and Paramount rather awesomely tolerate unauthorized fan productions as long as the makers don't profit from them.
Awesome Star Trek images from DesktopStarships.