I recently bout an oil pressure gauge and am not sure of exactly where to tap the hole in the engine so that i can get it to work--if anyone can tell me exactly where to put it your help would be greatly appreciated---o yea i have an 05 GS500F

There is a plug on the right side below the rotor cover.

If you look at your manual it should show you a couple places you can hook it up. The stock presure sender (for the idiot light) is under the right side cover for the ignition pickup, you could swap that out. Also, below the cover is another place (you don't need to remove the cover to see it)  that the manual states you can hook up a gauge. That one would probally be best as you would retain the idiot light.

I have been considering doing this, but I'm broke and lazy. Did you get an electrical one or a mechanical one? I think electric would be best, so that the oil line won't flex with your steering, and break, which could cause you to loose your oil. If you go with a mechanical one, I would sugest some type of braided hose, or other type that can flex well.

Let me know how this works out, as I'd like to do it too.
good luck 

mechanical but i mounted the gauge in the dash instead of on the steering wheel so as is wouldnt have to flex as much and thanx for all your help

Post a pic, I would like to see this.  I am entertained by simple things haha.