Hey! Don't make fun of my title!
So to start, I'd like to talk about some resource sites and why you should love them.
A good place to start for information is the hunter forums. The hunter community is quite active and in my experience very helpful. Just make sure you've already taken a peek at the stickies(the articles at the top of the page with the yellow paper icon next to them.) and have generally tried looking for your answer before making a post on the forums. As with any online community "flames" are a danger, but if you make an attempt at finding your answer before making a brand new post you'll get some helpful responses. Just browsing around and looking at what other hunters are talking about can be a great way to tell if you are on track without making your own post.
Wow.com is a good place for general info as well. Obviously because it's a site dedicated to all of WoW they can't go too in depth, but it is a good place to catch changes and some theory crafting. If you look at nothing else on wow.com check out the hunter based article: Scattered Shots*. This article tries to keep hunter's up-to-date on the most recent hunter changes and stuff-you-should-know.
*Something interesting I noticed in putting this together: The author of Scattered Shots, Jessica Klein, is not listed in wow.com's Team section. The last article was written on April 30, and I know there have been some significant hunter changes since then. Hopefully this article has not been discontinued, though I fear it has. I'll see if I can look into it.
*EDIT* So in reading The Tuesday Morning Post on wow.com I found out that Scattered Shots is indeed getting a new writer.
They're elitist, they're jerks and they're who you should go to for any and all raiding information. Their theory crafters and number crunchers are out of this world and I highly recommend that you check it out. It can be a bit daunting at first; there is a lot of information here, but at the very least grab the DPS Spreadsheet. This spreadsheet can read your gear, gems and enchants from the armory and give you an estimate of what sort of damage output you should be seeing. You can also fill out raid buffs, self spec, pets spec and a multitude of other information. I mostly use the spreadsheet to calculate upgrades, since it can be difficult at times to tell if gaining X agility and Y critical strike is worth sacrificing A hit and B attack power.
While petopia won’t tell you what pet to get, it does provide a plethora of information about pets, what they do, and where to get them. If you already know you want a spider, check it out to see what skins are available to tame. If you want to compare a cat’s abilities and a wolf’s, check it out. If you want to know what pet is the best in a given situation, look someplace else. In that case, elitist jerks or the WoW hunter forums might be a better resource. Petopia is great for general information, no so much for specifics.
I think that’s enough for one post, don’t you? These basics should get you started. Just remember, when in doubt, ask the forums. Just make sure you put on your fire resist gear.