The Obama campaign have launched an application for the iPhone which I'm sure will be loved by political junkies across the world. Alongside all of the features that you'd expect, like updates on the campaign and Obama's position on various issues, it has a few features that make use of the features of the iPhone. It hooks in to the iPhone address book and lists contacts by state, highlighting the battleground states and giving users a score based on how many of those people they have called. The application was built by volunteers and is a great example of how one constituency, geeks, are getting involved in the political process. I wish people were as engaged in politics in the UK.
Take a look at Obama '08 on the iTunes store: http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=292168926&mt=8