, a $5 download from the App Store, lets users listen in on police, fire, and EMS streams from around the world (much like ). The new version, released during Macworld Expo adds social networking capabilities. Now users can alert one other via text message about activity on the emergency streams to which they're listening. Something going down in Los Angeles? You can notify other Police Scanner 2 users by way of s small ticker in the app.

That's just the start of the social networking features planned for Police Scanner 2. The folks at Juicy Development tell me a update that adds integration with Facebook and Twitter is already under review by Apple.

Police Scanner 2 also lets users record snippets of a stream for playback later. Those recordings can be as large as the available memory on your iPhone or iPod touch allows.

Juicy Development says that Police Scanner 2 offers 2,300 emergency broadcast streams from nine countries--some provided by but others that an employee at the developer's Orem, Utah headquarters tracks down. "We have a lot of feeds that nobody else has," Juicy Development's Tod Hadley said. "We're searching nationally and internationally for feeds that RadioReference doesn't have."