This has grown louder and happens more frequently now than it did yesterday. It sounds like a high pitched metal on metal sound I hear it while driving straight, turning, in gear, out of gear, low speed, and high speed. Braking reduces or stops it temporarily.

I never hear the sound while at rest. Revving the engine at rest does not reproduce it either.

It sounds like it's from the front left wheel area, but it's possible I'm wrong due to my position while hearing it.

Any ideas?

 

I don't own an S2000 as of yet, but I know of one person who does have one who has already replaced a wheel bearing, and it sounds like that's what's happening here by your description.