An Opera developer writes up a comprehensive overview of the state of the mobile web design industry. Let me summarize, since it’s a long article:

• The iPhone is one slice of a much larger mobile market
• Mobile browsers are divided into two categories: full-featured (Opera Mobile and Safari) and constrained (WinWAP, Pocket IE, Blazer)
• Javascript support on mobile devices is uneven, always provide a fallback
• Design for 240 x 320; assume you’ll have a limited color palette to use and limited control over typography
• Plan for two distinct user experiences: Don’t ever assume that your web-based user experience will be the same on a mobile device
• Build one site that degrades well on mobile devices instead of building a second website just for mobile users
• Make use of the “handheld” media type for CSS