Yet another already-existing option is m.facebook.com. It's not full-featured (neither would an app be) but it is fast. (See this for more useful mobile URLs.)

I think we should encourage sites like FaceBook to create mobile versions of their site INSTEAD of iOS apps. Because their mobile site will work for us just as well as it will work for an iPod. But "there's an app for that web site"? Stop the insanity!