Usability 
BBC Sports generally provides excellent Olympics coverage and I expect this year to be no different.. The site offers news, results, photos and Olympic quizes. At this point there are only a handful of news items on the site but this will surely change once the games get started.
The BBC also has some free Olympics mobile wallpapers for download in various sizes.
Typical of BBC Mobile, page and image sizes are small enough to work with virtually any mobile browser. There's even a version of the site for old WML-only phones.