Although I try to showcase apps that are useful to lawyers in their practice, I'm not sure this one completely qualifies - unless you criminal defense lawyers out there can find a use for it.
The app is 5-0 Radio HD Police Scanner, and that's exactly what it is - an iPad version of the police scanner, and at $4.99 it's a lot cheaper than a real one. Even better, it provides access to police scanner broadcasts from all over the world. When you first log in you will see a catalog, where you can choose to Browse Scanner Feeds, see the Top 100 Scanner Feeds, or even add your own feed.
The Top 100 Scanner Feeds page shows you the top scanner broadcasts in terms of listeners.
Just select a feed, and start listening!
Most of the good feeds are located here in the U.S., but you can also listen to police in the U.K, Canada, Australia, Italy, and other companies if you like - but as you might imagine, the conversations in other countries aren't nearly as interesting.
The app also provides links to radio stations around the world, but if you're interested in listening to music I would recommend the TuneIn Radio app over this one. For the police scanner buffs out there, 5-0 Radio is a must-have.