Marty, I drive my car as if my Golf didn't exist; last November, it was essentially entirely new. The more you drive, the more the small sounds the car makes will begin to "talk" to you.
After a while, you'll be able to tell what noises are normal and which ones are worrisome. The belt noise you're referencing is perfectly normal if the belt is new or past the halfway point of its life span, and it should have about a half-inch of play in it when the engine's shut off.
That squeal occurs when the belt is first flexing under load. You're asking the outside of the belt to flex with the centrifugal force of the pulleys while the inside of the belt initially warms up and stays in traction against the metal halves of the generator (or alternator) pulley.
There are variables, but assuming the pulleys are shimmed to be exactly one over top of the other, that belt will quiet down once it's warm. Generally, letting your car warm up for three minutes or so before driving it will allow the belt (along with everything else) to come up to operating temperatures acceptable for driving.
Once the belt is warm, the noise should subside. Over time, as the natural rubber on the outside contact surfaces of the belt wear out and become 'glassy' in appearance, that squeal will come back. It's time to replace the belt when it squeals under normal operation.
Hope that helps.
