I'd venture to say that the majority of users here are iPhone owners. Assuming that, how is it possible that there is not an iPhone friendly version of MacRumors and the forum yet? A mobile version of the site or even an app would be a great idea.
If you click on the forums link in the upper left of the mobile.macrumors.com page, it should take you to the mobile versions of the forum pages. You will have to log in again, because it's a different domain name and so a different cookie (I guess).