Raid questions

So, I'm about to expose how much of a noob I am, at least when it comes to raiding. I've played a lot of WoW over the years and typically I've done all solo questing and 5 man dungeons but have never participated in a raid or anything requiring more than 5 people.  The guilds I've been involved with in the past just never got into the whole raiding thing and I've never sought it out. I feel like I am missing out on a significant amount of content. 
 
I'm going to be putting on a significant push to level 85 over the next few weeks (I'm close to 74 now) so I'm looking forward to the whole raid aspect. Since I have no knowledge of raids I have a lot of questions obviously. 

Is there any important reading I should look at regarding raids? What does a "progression" raid mean? Should I start getting set up with raid gear before I get to level 85 or all important raid gear level 85 only? 
 
Any help you guys and gals can provide would be greatly appreciated. 
 
-Jonnyflash

This is probably a longer answer than you want, and if you already understand some of these concepts, sorry. 
 
In general "progression" raiding refers to the current tier of raid content, which currently includes The Bastion of Twilight, Blackwing Descent, and Throne of the Four Winds. More specifically, a "progression boss" refers to a boss your group is currently learning and hasn't killed many times. This is in contrast with a "farm boss", which you know well enough to down on your first try each week, or at least down within a few tries. 
 
All content is gated by gear. Don't worry about hunting for gear before you're at level 85, because you can't get it before you're level 85. The basic progression is to run normal level 85 dungeons to gear up for heroics, and then run heroic level 85 dungeons to gear up for raid. 
 
Your general gear level is based on your average item level, which you can see on your character sheet. Each piece of gear you equip has an item level, which is a measure of that item's quality. Items level 333 come from normal 5-mans, level 346 come from heroic 5-mans, level 359 come from normal raid instances, and level 372 come from heroic raid instances. 
 
When you hit 85, you'll want to start working to get your gear to whatever the minimum level is to queue for random heroics. I don't remember the number, but you can find it by opening the dungeon finder (I). The system won't let you queue if you're average ilevel isn't high enough. However, there's nothing stopping you from rolling with some guildmates, which I'd recommend. 
 
Once you start running heroics, you want to collect as many pieces of 346 gear as you can before you start raiding. You'll get these items as drops off of the bosses themselves, but you can also buy gear from the Justice vendor; you'll gain Justice Points from each boss kill, which you save up to buy gear. I'd recommend using Wowhead to find upgrades; for example, here's a list of every cloth item between ilevels 333 and 346 with Intellect but no Spirit. (It's my understanding that Warlocks don't need Spirit, but maybe somebody can correct me if I'm wrong.)
 
As for raiding itself, I couldn't link you to any general guide on raiding, but before you go into a boss for the first time, you should read up on the mechanics so you're not going in completely blind. You also need to have an understanding of how your class does DPS, and as a Warlock, you should know how to control your pet. (Which mostly means, put it on passive so it's not hitting things it shouldn't be.) My best guess is that the first boss in this tier of raids you would see is Halfus Wyrmbreaker, who, all things considered, isn't that complicated if you're just DPSing. Fights like Magmaw and Omnotron Defense System will require more situational awareness on your part.

Thanks for taking the time to type all that gakon. This is unbelievable helpful. I can't wait to hit 85 now so I can get started on gearing up.
One more question. Do enchants or socketed gems affect the average item level at all?

Actually, there is something you can do before you're level 85 to prep for raiding. You can get blue and purple gear from the various reputation factions in Cataclysm. Obviously doing a faction's quests will increase your reputation with them, but also doing level 85 dungeons with that faction's tabard equipped will increase your reputation as well. 
 
Here is a list of gear for your class which you can get from reputation (each item's tooltip shows the reputation required to buy and equip it). You won't be able to start working on these reputation grinds until you start the Cataclysm zones, however (between levels 78 and 80).

Glad to see you looking forward to raiding!

My biggest recommendation is push for 85 and then using pvp auction house gear we should be able to get you to 329 ilvl pretty easy. Then you can roll with us as we do random heroics.

As far as raid strats

Oops hit submit, anyways search for omfgcata on YouTube and then go to his boss strategy playlist.

We aren't to heroic raids yet. Our current progression boss is ascendant council.

Me and babble will gladly help you with any lock issues you have and any of the current raiders I'm sure will gladly talk to you about raiding.

It's great, it's the most fun I have had playing wow and I have been playing since launch.