Usability 
Phoenix AZ Valley Metro offers an interactive trip planner, static schedules, service advisories and maps in .gif format. The maps are resized on the fly to fit various mobile screen sizes ranging from 96px to 320 px in width and should load on almost any phone, although they tend to be hard to read in the smaller sizes. There are links to PDF maps too although the ones I tried didn't work. There are also turn by turn text descriptions of each line's route which is probably even more useful than the maps.