Another method is to use something completely metal like a wrench or something. Put one end to the bottom of the block, and one to your ear and use it as a stethscope if it is obvious it is in the bottom end it is probably a bearing.
If/when you have the chance to do these, if it appears to be a bearing, pull the pan and make sure.
As far as knowing about it while driving. I've havn't had it personally happen, so I can only say what I've heard from others. You'll be picking up alot of knock, which I would assume the ECU would retard timing (loss in performance) as a result. Also you should see a loss in oil pressure...however, being that our stock gauges are crap, you may not even notice it
Oil light may come on.
I seriously would get it towed, and not drive it. I mean look at it this way, if you drive it and it is a spun bearing you are now getting that oil filled with metal shavings going through your turbos. Also if by some miracle your crank is still ok, it wont be for long.