Nature Publishing Group just announced a new iPhone app that allows you to access science news stories and the latest published research. The app is free.
I installed the app, and while I can't vouch for the accuracy of the science, I can say that the app is rather lacking in abilities. You can't change the font size, annotate or bookmark. All you can do is save an article for later, copy, and view the article in Safari. Still, I think the content outweighs the shortcomings.