I had always hoped to do an iPhone interface for Transit Surfer, using the iUi toolkit to build a web interface that mimics the native iPhone UI.
But Andrew Wallace, a local developer, has beaten me to it and gone one better. He’s written a native iPhone app that uses TriMet’s web service to get arrival data. And he’s working to add Streetcar to it. You can get the app for free from the iTunes store.
Of course, Transit Surfer still has some unique advantages :-)