Where is ames in Metal Gear Solid 2 and what are you supposed to do with him once you find him

I believe Ames is the guy in the hostage situation with the pacemaker.
If you equip the microphone, and 'Aim' with it, you should hear a bleeping sound when it's in his direction.
If i remember correctly, he is towards the end of one of the rows, is facing down, and has white hair (possibly a blue suit).
Use the microphone and listen for the beeps is the best advice i can give.