I have Action Scanner, Police Scanner, Police Radio, Scanner 911, Emergency Radio, 5-0 Radio, Pocket Tunes, and Wunder Radio all on my iPhone 3G. (All of them work on Edge!)
Not all apps are created equal and not all apps have the same feeds available.
Action Scanner by far in my #1 favorite!! With the ability to scan thru up to 4 different feeds at the same time...it is the closest thing to a real scanner as you can get in an app right now...and they have my Feed in there database...Love it!
5-0 Radio is my #2 favorite. Very clean interface...nice big clock telling the current time, they have my Feed in there database...and it tells how many people are listening. Its great for me being a Feed provider...I always know how many people are listening.
The rest I could take or leave...nothing special about them, some do not update their database very often at all. The only other app that I like that is well worth talking about is "Pocket Tunes" If they ever updated their database...I would Love this app. First of all it is not a Scanner feed only app...it covers all types of audio feeds. Now where this app is different and really has potential is...you can hit a button on the screen and actual record the audio you are listening to. This is a really cool feature that I use alot for music...but since they don't have my feed in there database...I hardly ever use the app for scanner listening.