A lot more companies than you might think have mobile websites but they aren't always easy to find. Often, the site won't sniff your browser string so you get the full site, or you may have modified your browser string so your bank won't ignore your browser. If that is the case, you might want to add some of these links to your favorites folder.
Those are a few of the mobile sites I frequently use. Twitter has one of course, but it automatically detects your browser, as do the Thought Media sites. Do you have any good general interest mobile links for sites that don't automatically redirect your browser?