i worked at my friend's (non-dealership) shop to fill time and pay for parts for a race bike. but honestly, my buddy - the owner - really just didn't make much money. the best part for me was the comraderie with my racing buddies during and after work.
i also have another friend that owns the kawasaki dealership where i bought my first bike. his wife works with him. the dealership is open 6 days a week. they have 2 kids that have grown up in the dealership. their crib was the area under the desk with the pc. it was always funny to see them selling bikes while trying not to step on the kids.
i have another friend who went to MMI. he's not a mechanic anymore because working on bikes made hiem not love bikes.
i figure the best way to get the experience is to do what i did... work for free at a friend's shop. it allowed me to work on the bikes on the weekend and learn by osmosis.
if you really want to work on bikes, get the job - just don't expect to make much money. the real payoff is when you can be doing what you love or being around your friends.
and if the gf/wife isn't into bikes, it will get ugly because they might not support ya spending all your time getting greasy for no money.
so there's my not a pretty picture. but all said, that year at my buddie's shop was the best year of my life. broke. but always around the bikes.