With all the explosion on Mobile Web and Applications. Theres’ several offerings that let you create mobile web. Some great things to keep in mind is how your application will look like in the several mobile browsers that are out there, such as Mobile Safari (iPhone, iPad, iPod Touch), Mobile Firefox (Android and others), Mobile Opera (Several platforms).
37 Signals goes into details on how to watch out for these issues and the solution of-course.
What they learned from building UI from 37Signals.com