Most radio shack scanners are made by a company called GRE with a few being rebadged unidens.
Some radio shacks will program a scanner for you, mine did but the frequencies they loaded were all useless so I cleared it out and started over myself.
Be careful about letting the scanner re-charge the batteries, most are a simple dumb charger which is simply a trickly charge circuit at a slow enough rate to charge most any type of battery safely but doesn't give the best life. I liked the pro 97 because I could pop out the little battery holders so I could charge one set in a good charger while the running the scanner from another set.
Analog and digital when referring to scanners has to do with the type of trunk systems it can decode, not the type of tuning. All are digitally tuned. You want to look at a dateabse like radio reference and determine if you can do with a plain old non trunked or need analog trunked or digital trunked. If you do go with a radio shack then wait for them to go on sale (watch the RR forum, someone will announce it), for example my $199 pro97 went on sale for $149.

Your local Radio Shack should have at least one employee there who can tell you what type of scanner you need, and whether they use analog/digital/trunked/whatever. Probably the manager of the store is the best guy to talk to.

If you can get by with analog, I recommend something like the following:

http://www.yaesu.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID=103&encProdID=rHqQH%2FVccfo%3D&DivisionID=65&isArchived=0
http://www.icomamerica.com/products/receivers/r5/default.asp

They will be a bit more expensive than a plain analog scanner. They also might not scan as fast. But they are a LOT more useful, as they also pickup shortwave, am/fm broadcast, television audio, etc.

** EDIT **
A lot of places have laws against using (or even having scanners) mobile. Specifically, I have heard of states in the southeast that confiscate any scanners in a car -- even if handheld and in luggage for use by race fans hoping to hear their favorite driver talking. However, AFAIK, all states have exceptions for amateur radio operators. So, if you study and get your ham license (cheap), then you can legally own a scanner even in a car.

KY and NY are two states I recall that don't allow scanner use.

Really? Even in luggage?

I'm joking, of course, but if I buy one of these confiscated scanners at a police auction in the southeast, how do I get it home?

Threads on radio reference confirm that. The KY police are supposed to take it and run over it with their car. My SIL lives in that state so I have to leave some gear behind when we go there, thankfully we don't often since they still allow people to poison others with nicotine in public.

The Ham Ticket - that's important to have for a Scanner owner. It's the main reason I got a ham ticket in the first place.

http://www.afn.org/~afn09444/scanlaws/scanner5.html

I don't know about the analog or trunking...it's geek to me. But I will say stay away from any radio shack product that has a rechargeable battery. I Had a really nice Pro something while in college. Really fun listening to those cordless telephone calls back in the day...anyway..fast forward a few years and you can't get a replacement battery. Just my advice. Same problem with Craftsman cordless drills.