Guild members have been putting 10 man raids together for Onyxia a little lately.  I found a very easy to read and succint strat at [url=http://wow.zuggaming.com/2009/09/25/onyxias-lair-boss-fight-strategy-guide/]zuggaming[/url] in case it's helpful... 

Onyxia’s Lair Instance Strategy Guide: Phase 1

&#9632;The first phase of the new Onyxia’s Lair instance is your basic tank and spank.
&#9632;The Broodmother uses her abilities Flame Breath, Cleave, Wing Buffet, and Tail Sweep during this phase.
&#9632;Keep your tank positioned in front of the Broodmother.
&#9632;You’ll need 2-3 healers (for the 10-man version), who should stay on the Broodmother’s sides.
&#9632;Healers will have to heal tanks through Flame Breath and Wing Buffet.  For this reason, ranged DPS and melee DPS should also stand on both sides of the Broodmother.  You can’t afford to have your DPS in the way of either of these attacks.
&#9632;When the Broodmother gets down to 65% health, phase two of the new Onyxia’s Lair instance begins.

Onyxia’s Lair Instance Strategy Guide: Phase 2

&#9632;When phase 2 begins, the Broodmother spawns Onyxian Whelps.  Most of your DPS should focus on the whelps and wipe them out first before switching back to the Broodmother.  More whelps will spawn every minute and a half until phase 2 of Onyxia’s Lair is complete.
&#9632;During phase 2, the Broodmother uses her abilities Fireball and Breath.  Before she casts Breath, she emotes about taking a deep breath.  This is your cue to get out of the way.  Players hit multiple times by Breath will die.  Fireball does a decent amount of damage, but it’s less of an issue than Breath.
&#9632;The Broodmother also spawns an Onyxian Lair Guard about every 30 seconds throughout phase two.  Use your backup tank to tank the guard, and melee DPS should switch to the guard.  Ranged DPS should keep attacking the Broodmother.  Make sure your backup tank has his own healer whenever he’s tanking one of these guards.  The guards have 190,000 health points, and their melee damage is quite substantial.  The added fire damage from their abilities Ignite Weapon and Blast Nova makes them an important part of phase 2.
&#9632;When the Broodmother gets down to 40% of her health left, phase 3 of Onxyia’s Lair starts.

Onyxia’s Lair Instance Strategy Guide: Phase 3

&#9632;Phase three is where the Broodmother’s abilities Eruption and Bellowing Roar come into play.  She also spawns a few whelps.  Basically phase 3 is another tank and spank fight, similar to phase 1, except you’ve got to stay off the cracks because of Eruption.


Here's a list of her abilities:

Bellowing Roar

&#9632;Causes fear
&#9632;1.5 second cast
&#9632;100 yard range
&#9632;Lasts 3 seconds

Breath

&#9632;4,000-5000 damage per hit
&#9632;Fire damage
&#9632;Hits multiple times in one cast
&#9632;Hits all party members in a straight line in front of her
&#9632;6 second cast

Cleave

&#9632;100 percent weapon damage

Eruption

&#9632;5,000 damage
&#9632;Fire damage
&#9632;Lava comes up through cracks in the floor
&#9632;Cast during Bellowing Roar

Fireball

&#9632;5,000 damage
&#9632;Fire damage
&#9632;2 second cast
&#9632;Cast on any one party member at a time
&#9632;10 yard range

Flame Breath

&#9632;20,000 damage
&#9632;Fire damage
&#9632;2 second cast
&#9632;45 yard range

Tail Sweep

&#9632;5,000 damage
&#9632;Physical damage
&#9632;Knocks you back
&#9632;Hits anyone close to her tail

Wing Buffet

&#9632;15,000 damage
&#9632;Physical damage
&#9632;20 yard range