I will second ky-las' suggestion for KLAS being a great place to listen to helicopter traffic. When listening to the KLAS feed you'll hear Landmark and Maverick callsign's a great deal of the day. Most of the time you'll hear them saying "<callsign>, garage, 3,000", just after departing the ramp, then be cleared for the Trop. departure. They follow Tropicana Blvd all the way east for the tours. My house is just south of Tropicana on the east side of town and I'll sometimes see 4-5 helicopters flying out for tours on weekends. It's a amazing site to see them all lined up on their way out.
It's weird how it worked out but the office I work in is right under the Callville arrival, around Industrial and Desert Inn, so I can see them come as well. I wish I was able to put up an antenna at work.