Just because you asked, here's some more information on the arena system. Hopefully this quells some of your concerns, and squashes a few assumptions. Please keep in mind that this information is subject to change, but these are our current plans for the PvP Arena system in The Burning Crusade expansion.
When a player enters an arena battle, all buffs and conjured items are purged/deleted. This is done to ensure no outside buffs or items from members outside of your team are able to be used in an arena battle.
No consumables other than bandages and conjured items can be used while in the arena. There will be a waiting area similar to the current battlegrounds where players on the team will be able to conjure items and cast buffs.
Abilities/spells/items with cooldowns longer than 15 minutes cannot be used while in the arena.
Each arena team will be given a rating, and will be matched up in the arena queue against teams of a similar rating (matching within that specific cross-realm battlegroup). As time progresses the matching system will broaden its search up to a limit if a closely rated team cannot be found.
Ratings adjustments are made in the same way that ELO ratings adjustments are made. This system works by adjusting each arena team's rating from a specific match based on the rating of the team they are up against. If a team wins against a team of a higher rating, the increase of their arena rating would be much higher than if they had won against a team of a lower rating. This system will help promote players improving their skill and besting teams which may have previously held the top spots.
At the end of each week, characters receive arena points based on their team's rating. A team must have fought a minimum number of battles for the week, which we have announced as currently set to 10 games. A player must have played in at least 30% of the team's battles that week in order to be eligible to receive arena points. Each eligible player will then receive a fraction of the teams total awarded points to spend on arena rewards.
Players may spend their points on arena rewards, or save their points until they have enough to get the rewards they desire.
There is a limit to the number of points a player can stockpile, which is currently planned to be as high as the most expensive item.
At the end of a season, players on a team are given a title based on their team's relative position on the ladder which will last through the next arena season.