incarceration

so i've hit my 3,500 mark on my car. and i've made a previous thread about this. i'm still hearing a noise when i get to about 70MPH-100MPH.

it sounds like someone screaching their tires but a kind of vibrating noise. or like something's bouncing around or loose inside my dash and\or engine compartment.

what could it be? it's on the passenger side. should i tell my dealer? should\would the dealer find it and fix it (i got it on 7/1/2006)

any advice and tips will be greatly appreciated.