I can give you an answer, because in the last 5-6 weeks I create a web app which should be suitable for mobile browsers and dektop browsers and I can tell you, it works.
Tested with Firefox 3.6., FireFox 4beta, Opera, Google Chrome, Safari. IE9, I have some optical design problems, but the functionality is given. IE9, I have to do some modifications.
But if you want on desktop and mobile browser, you have to do many things with % width's, otherwise you will have problems.
Best Regards.
And here you have the open source project which works with iPad and desktop browsers:
http://bit.ly/nVimJKYou can get the source from GitHub and contribute to it if you like:
http://bit.ly/nR9QmH