Oil pressure too high?

Ok, I'll see if I can borrow a friends or buy a cheap pressure gauge.
Couple follow up Qs:
-Can I hook up my multi-meter to the pressure sending unit and use a voltage reading to see if the sensor and/or factory gauge is bad? Anyone know the conversion or where I could find it for this?
-If I'm going to hook up an aftermarket oil pressure gauge where would be a good place to hook into an oil passage? Or is it best to just go where the factory sending unit plugs in?

Thanks a bunch guys!!