Ah, Steampunk. What a wonderful concept! Let's start off with a short FAQ about steampunk for those new to the subculture.
What is Steampunk?
Very good question, and there are different (but similar) answers out there. Generally speaking, Steampunk is a genre of fiction set somewhere in the 1800's during the Victorian Era. The fictional part comes in that technology has gone a bit skewed - though the exact methods vary, generally steam-powered devices that would have been impossible or unfeasible at the time are found to exist. Examples include steam-robots, flying castles, under-water bases, moon rockets, time machines etc.
Steampunk has gone by many names and has very close relations, including (but not limited to) -
Victorian Science Fiction - Steampunk by any other name, though possibly leaning more towards fiction actually written in Victorian era, as opposed to fiction retroactively set in Victorian times. Abbreviated as VSF.
Gaslamp Fantasy - The Girl Genius equivalent of Steampunk, with more leeway for very tight bodices, slapstick comedy and non-humans. Not set in any real Victorian historical location, Girl Genius has its own time and place.
Fireside Science Fiction - A warm and cozy alternative name where decent Victorian gentlefolk may begin their adventure around a fireplace with a small brandy, but could end up on the moon or beyond!
Neo-Victoriania - A Japanese originated alternative where the aim is to recreate certain Victorian aspects of life using modern tools and ways. Elegant Gothic Lolita is a variety of Neo-Victoriania, and were this some kind of many limbed diagram, we'd be at our closest point to Gothic in Neo-Victoriania.
Wild/Weird West - Specifically focused on the American West in the 19th Century, and you'll find cowboys and scientists alongside saloon girls and giant mechanical spiders.
Voyages Extraordinaire - The title of the series of works of Jules Verne, when he decided to explore the wonders and potential of science and exploration in his tales of adventure. Now almost synonymous with Victorian adventures with a larger than life twist.
Scientific Romance - An early, mostly British, name for science fiction, that fell out of fashion, but was also used to describe Verne's works. Now being used more for nostalgic Victorian based science fiction - just how I like my Steampunk!
So, what, it's just a bunch of stuff covered in brass and gears?
Well, no. Brass and gears are just really well known in the subculture, like goggles. Anything that presents technology from a Victorian-era standpoint could be considered Steampunk.
Do I have to do anything special to be a part of this culture?
Aside from having an interest in it, not really. The great thing about Steampunk is that it's so widespread that your style involving Neo-Victorian clothing and/or tech could be completely your own, and it would still be greatly accepted by the community. Overall, just keep an eye on Steampunk websites (as well as this club!), and I'm sure you will discover your very own Steampunk flavour or equivalent.
You mentioned websites. What websites, specifically?
Brass Goggles is a great place to start. The Steampunk Home blog is also a good place to go. And, as always, the Wikipedia article about Steampunk is good if you're still clueless.