None of this is classified and can be gained thru media sources. I was looking over the troop list so far as the Army is concerned and speculate what the Marines have ready -
Army - 3d Infantry Division (Mechanized)
Army - 4th Infantry Division (Mechanized)
Army - 10th Mountain Division (Light Infantry)
Army - 101st Airborne Division (Air Assault)
Army - 82d Airborne Division
Army - the rest is classified but consists of Special Ops folks - let your imagination run wild here.
Marine - at least one if not two Marine Expeditionary Forces (the equivalent of a Division - or about 14,000 Marines)
With the exception of the 4th Infantry Division, all the Army units are part of the 18th Airborne Corps - to include the 3d Infantry Division.
The "Stealth" fighter squadron from Holloman AFB shipped out. Something like a 30-hour non-stop trip, to be refueled in route. The B2s already left and are present in theater somewhere. If I remember correctly B-52s struck from their home bases during Desert Storm, so I am sure they will do that again - plus some from Diego Garcia.
Pretty impressive array of forces. It does not include logistical support for the Army - the Navy provides it for the Marines, and who knows how much air power we have there between the Air Force, Navy, and Marine Corps. (Five carriers worth of Navy fighters and fighter-bombers - which is over 350 aircraft that are just Navy/USMC). I have already figured out my own scenario for how I would employ them, but would rather not speculate publicly.
I would also imagine that if Britain has not deployed regular troops that both Britain and Australia have sent in their special ops guys - most likely SAS. They would be working under a joint British/Aussie commander who reports to the US Commander on the ground - most probably the 18th Corps Commander or CinC CENTCOM.
The two mechanized divisions are already there. The 101st is closing (meaning finalizing their deployment) as is the 10th Mtn. The 82d is prepared, but does not need to deploy until they are needed. Marines are already afloat with the fleet. Carriers are on station. Special Ops guys - don't want to say.