An update to an already great app, version 4 of Instapaper ($4.99 in the App Store for iPhone/iPad) adds, among other things, a new icon, cleaned up typography, nicer colours and a redesigned logo. And there's a whole bunch of usability and technical improvements as well.
Instapaper is good on the iPhone, but if you've got an iPad, you should definitely pick up a copy if you enjoy reading at all.
You can listen to the first episode of Appsession where I talked about why I like it so much. I'll have to do an update of that episode with all the new stuff in version 4.