I came across some neat social media applications that you can share with people on Facebook, etc. These were created by a company called Metablocks.
Here's a widget they created for Tim McGraw. Neat implementation.
Here's another one they did for the Facebook page of MaryMary: http://www.facebook.com/MaryMary. They do a variety of Facebook fan page formats.
Since the size of these widgets is very similar to an iPhone app, my guess is that Metablocks can also make the widgets into iPhone apps that you could give away free.
Their motto: Social media apps for brands, bands, and business: http://www.widgetmatic.com.