I did listen to them for a while years ago, but several years ago they stopped because of copyright issues from the NFL. I didn't try it again until last weekend. Funny, the KOA site seems to imply that you can listen to the game, but when I actually tried, it cut out a minute after the kickoff, never to return. I tried a few other stations in the network, but never heard the game. I'd like to hear if anyone has success, if it is free and legal.
The NFL has made a rights deal with Sirius and the league also has its own pay internet audio feed, so they’re protecting those by having the regional stations block streaming. The Sirius coverage has both home and away broadcasts for every game.
A local station with the rights to carry the broadcast is probably violating its rights agreement if it fails to interrupt its internet stream during the game, but a lot of small town stations these days are fully automated. I don’t know what the legality issue would be to listening to something being broadcast on the internet by a station that has licensed the broadcast solely for local use. You’d think the liability would be with the station, not the listener.
The real legality issues attach to those sites that are streaming video coverage that they don’t have the rights to. The NFL goes after them, and after bars that are showing them. In those situations, you’re dealing with people who are knowingly using an illegally obtained feed.
Another big bootleg sports area is European soccer broadcasts, particularly English. Many of the shady sites are in the former Soviet Union.