Making your group:

You've hit level 85, and you're satisfied that your gear is good enough to go head to head with other players without taking too fierce a beating. It's time to get into Rated Battlegrounds. The first thing you're going to want to do is find a group of at least 9 other like-minded players. There are no battlegrounds that accept less than 10 players per team and if you can't field a full team you are out of luck.

As with most group activities in World of Warcraft you're going to want to have a relatively diverse group. The composition probably won't be as important as it would be in a raiding environment, but you are still probably going to want at least 1 healer for every 3-4 DPS in a rated BG situation. Ironically, unlike raiding, this is one situation where Blizzard's "bring the player not the class" mantra is fully applicable. Group yourself with players who are skilled and motivated to succeed since you'll need coordination and a high level of play but you won't get burned too much by running a weird or sub-optimal group composition.

You're going to need more than 10 people on some weeks and much more on others so it'll be important to network with other groups of PvPers since you may need to join forces for some of the larger battlegrounds. More info on that aspect of rated BGs can be found in the Rules and Battlegrounds sections.

Battlegrounds

Currently Blizzard is planning to have players participate in all of the available battleground types including the two new battlegrounds being introduced in Cataclysm. As a quick refresher for those who may not be up to speed, the battlegrounds available will be as follows:

      10 vs 10: Warsong Gulch, Battle for Gilneas, Twin Peaks

      15 vs 15: Arathi Basin, Eye of the Storm, Strand of the Ancients

The size of the battleground is important to know, because the Rated BGs available on any given week will be determined by the group size. On a 10 vs 10 Rated BG week you would queue up and be randomly placed in either WSG, BfG, or TP. Each week the schedule will rotate between 10 and 15 player Rated Battleground groupings. For this reason it is going to be vital to have a large network of players that you can call upon to play with you since some weeks you'll need significantly more players than others.

This is a preview from BlizzCon of how your Rated BG statistics will appear.

Rewards

Rated Battlegrounds will offer almost identical rewards to what you would receive from Rated Arenas. Battlegrounds will give you access to the high level PvP Tiered Gear as well as the infamous "2200" weapons available at high ratings. After each win you'll be rewarded with Conquest Points that you can use to buy these rewards. The amount of points you can earn in any given week is capped. The cap is based on your highest Rated BG rating from the previous week.

The only things that will be available exclusively through Rated Arenas will be the arena related titles and the special flying mount that is awarded to players that achieve Gladiator ranking. Rated BGers will receive a different set of titles.

[protip]If 80% of the people in your Rated BG group are from your guild you will be able to use this activity to gain guild experience for your guild![/protip]

Titles

If you're old school you will know all about the Vanilla WoW PvP titles, but those who aren't have probably seen players here and there sporting military rank-titles like "Marshal", "Sergeant", and "Warlord". These titles will be making a comeback in Cataclysm and will be rewarded to players who achieve certain levels of Rated BG rating.

The lowest level titles will be awarded starting at an 1100 rating and new titles become available each 100 points from there up to a rating of 2400 which will award the rare "High Warlord" and "Grand Marshal" titles. These titles will be permanent and will not be wiped with the start of a new season. Furthermore there will be two new titles -- "Hero of the Alliance" and "Hero of the Horde" -- that will be awarded to players in the top 0.5% of competition, much like the Gladiator title is for Arenas. These titles will be wiped each season.

Rules

Rated Battlegrounds will operate significantly different than Rated Arenas insofar as there are no more set teams. In order to queue for a Rated BG you simply must have 10 players in a raid group that are eligible to queue for Rated BGs (ie: level 85s). Each player will have a personal rating, much like Arena, but that personal rating will be the only relevant rating for Rated BGs.

Matchmaker rating will be making a comeback for Rated BGs. This is the system used in Arenas to determine what rating players should be as opposed to what rating they are currently at. So long as your matchmaker rating is higher than your personal rating you will never lose Rated BG rating. Blizzard will match you against groups of players whose amalgamated matchmaker rating is similar to that of your group. While this system seems rife with exploit potential (for example: add one geared but un-rated player to throw off the matchmaker rating of your team) it also seems like the fairest way to handle things and is one that Blizzard has experience at.

As explained earlier, you must have the proper amount of people for the group size that is being featured that week. You're not going to be able to queue up for a rated 15 player BG when it's 10 player week.

All in all it’s not complicated. The BG system has been designed to be something that everyone can enjoy and doesn't have too much of an organizational component. Look forward to it!