Some other thoughts to ponder:
There are three different routes you can take to serving mobile content. You could serve different sites to different devices via server side scripting, you could set up a subdomain (
http://mobile.example.com/) and serve the mobile site from there, or you could use a mobile only style sheet.
My suggestions above were NOT for setting up a mobile style sheet.
For mobile stylesheets, it is criticial to ensure that you avoid using IMG tags in your markup when they aren't semantically required. Basically you want to avoid images wherever possible as they're a killer for mobile sites due to the size of each image download. If you display the images using CSS then you can either serve smaller versions or none of those images to mobile devices.