A big community of developers are starting to form around the idea of developing Web applications for the iPhone. There was even iPhoneDevCamp last weekend.
One of the best apps that i’ve seen come out for the iPhone is Movies.app (http://www.moviesapp.com). It’s great for looking up movie times at your local theaters. The whole application uses the inherent iPhone interactions really well.
You can search for listings either by movie or by theater.
Once you’ve found the movie of interest, beyond seeing just the times, you take a link to the movie trailer or get a map to the movie theater, using the iPhones Google Maps application.
It’s pretty slick and I’ll probably use it a lot.
Oatmeal Stout - Justin Thorp's blog 
What I find particularly remarkable is that the author said that he wrote this in about 5 hours because he was able to use Joe Hewitt’s framework as a base.