Oh and here is a video on youtube of reverse thrust being deployed on a BA flight landing at LBA.

http://youtu.be/_6z2wQRohYg?t=1m37s

On touchdown at 1.52 you can see the door opening towards the back of the engine, and the engine noise increasing as the thrust is diverted forwards rather than backwards. The pilot releases the reverse thrust once the ground speed reaches 60 kts - the pilot monitoring usually calls out the speed I believe.

EDIT: also when the video pans over the engine at 1.58 you can see the speedbrakes are up to reduced lift and transfer teh weight to the undercarriage so the wheel braking can work effectively.