BI have just announced an upcoming DLC pack for all versions of ArmA 2!. This is thier first shot at a paid DLC system. Unlike other games that ofer 4 or 5 missions, you get a whole lot of content for a small price. Here are some screenies: 

Arma 2: British Armed Forces key features:

• New vehicles and weapons
• Modern British troops in multi-terrain, desert and woodland camouflage
• Personal weapons: L85A2 and L86A2 rifles, L110A1 machine gun, LRR and AW50 sniper rifles, N-LAW AT launcher
• New vehicles: Jackal 2 MWMIK all-terrain vehicle, modernized FV510 Warrior
• New helicopters: AH11 Wildcat (multi-role), HC3 Merlin (transport)
• British versions: off-road car, Chinook HC2 transport helicopter, Apache AH1 gunship
• Desert and woodland paint schemes of the ground vehicles
• New single player campaign
• Player will command a mobile observation team of British troops into battle with Takistani insurgents. Short campaign will focus on depicting asymmetrical warfare with a guerilla force and counterinsurgency operations.
• Multiplayer modes
• Cooperative scenarios featuring the British units, vehicles and equipment.
• Engine Improvements
• Extension of the Engineer's role
• Ability for players to effectively operate and command artillery and mortar units
  

Arma 2: British Armed Forces will be deployed exclusively for PC on 26th August 2010. It will be available for GBP 7.99/EUR 8.99/USD 9.99

Check out all the ranting and raving in the BIS Forum.