Bic,
What you need is a simple analog VHF/UHF scanner. Don't be fooled into getting a "trunking" scanner or a digital one. Yes, most law enforcement has gone that way, but for the frequencies you listed all you need is a simple analog scanner. If after you gotten your feet wet scanning this simpler frequencies and you want to progress to a higher level of scanning then you can think about the more advanced scanners.
Radio Shack, Fry's, Ham Radio Outlet and Amateur Electronic Supply are a few of the national brick and mortar companies that sell scanners. Of course they have on-line stores as well. Here's one on-line dealers that might be of interest. Not recommending them, just the first one I came to.
http://www.scannermaster.com/Police_Scanner_Radios_s/1.htmFirst decision is whether you want you scanner to be a "base" station (120vac) or you intend to mount it in the car and run it off 12Vdc, or whether you want a handheld (battery powered) one to carry around with you.
Uniden, Radio Shack and Whistler are all market basic scanners. Here's a basic list from the same company.
http://www.scannermaster.com/Uniden_Bearcat_BC355N_Police_Scanner_p/10-501825.htmAll air traffic control comms are sent in the clear (unencrypted) and are fun to listen to. ATL and other big airports have many frequencies and it's hard to listen to everything. But smaller airports may only use 1 to 3 frequencies are easy to monitor (as well as USAF bases). I was in Roanoke listening to the tower one afternoon and heard my flight being diverted because of fog. I was the first one at the ticket counter to rebook because I had my scanner with me.
True most police and fire are digital, trunking systems, the complexity you probably don't want to tackle with you first scanner. But here's a little secret about fire departments. Usually their dispatchers are simulcast (repeated) on an analog frequency for backward compatibility, so your scanner can probably monitor fire dispatch even if the whole county is digital. You probably won't be able to listen to individual fires as they take place, but dispatch tells you a lot.
Highway patrols, Wildlife Management and Natural Resource (DNR) (think game wardens) tend to still use the VHF analog frequency in rural areas because the super fancy UHF digital isn't reliable away from the population centers. So there's always possibilities to listen there.
A number of federal agencies still use single frequency units for operations. And while they are usually encrypted just the volume of activity tells you something is up.
Maritime went from HF to VHF back in the '70s. On-line you can find a whole list of frequencies. 156.8 is the primary contact frequency, but there are also ones set aside for bridge tenders, harbor operations and SaR ops. I always listen to 156.8 (channel 16) when I'm at the beach.
At home, since I live near a country/golf club, I monitor their maintenance frequency. And many shopping malls have simple analog radios for their ops, maint and security as well. Many years ago my buddy and I were going to the food court and pulled up just after a shooting had occurred. We sat in the car and listened to both the police activity (not much) and the mall ops for an hour. Never got lunch.
Some of the "itinerant" frequencies you mention are part of the GMRS and FRS system.
I have a little spiral bound notebook that list all these frequencies by function so that if I'm somewhere or something happens I have a quick (off-line) reference to them.
Hope that's enough to get you started in scanning. I have 3 dedicated base/mobile scanners, plus all my ham radio VHF/UHF transceivers have wide range receiving capabilities. I take my handheld (walkie-talkie) VHF/UHF radio on all trips and use it as a scanner.
Alf - W4ADS