If you want the definitive source on CSS design, there are few sites comparable to A List Apart so you can expect their guide to designing for the iPhone to be worth the read.
These tips for designing Web pages for the iPhone, like many of the articles on the web site at AListApart.com, are for experienced designers — you’ll need to understand the basics of CSS and web page design to follow them – but if you’ve got that covered and you’ve been looking for help adapting your CSS designs for the iPhone, you should definitely check out this article by Craig Hockenberry on AListApart “Put Your Content in My Pocket.”
