Keep in mind that the viewing area on a mobile device is a whole lot smaller than that of a computer monitor. So you need to be short and concise. Plan on about 10 text lines per WAP "card" (instead of "page.") Due to slow transmission speeds typically 14.4 to 19.6 Kbps you need to keep text and graphics down to bare minimum.
Wireless phones use "microbrowsers" to surf the web so you need to make sure the web cards in WML look good on a wireless device. But what if you don't have that kind of luxury? No problem, hop over to http://www.wapdrive.net and you'll find something called "The Wapalizer" that will allow you to look at any WAP site using your regular browser. Just type in the URL and a new window opens up that imitates a mobile phones interface. You can browse through the entire site to make sure everything will be viewed correctly by your mobile guests.