Some pro-radio resources you might enjoy:
RADIO WORKS jingle package from Creative Radio
RAB's Why Radio? page - good material for building your own pro-Radio spots.
Radio: It's Always On - Radio Mercury Award finalist from Entercom/Portland
Woodpecker - WBEB-FM's 2010 Radio Mercury Award-winning commercial on...what else? ...Engaging Radio.
Larry Fuss's Radio Advertising Facts website
If you have some favorite pro-radio resources or spots of your own, please share them in the comments section below!