The official list is here:
http://www.roku.com/channels/#!brows...her/by-popular
(that's news and weather...you can select other categories to browse)
There are several unofficial lists, here's one:
http://streamfree.tv/apps/index.php?...s&ascdesc=DESC
Some of the private channels are free...some require subscriptions...some are live...some are not...some work...some don't. It's a mixed bag.
Time Warner Cable recently introduced a Roku channel that lets you view content based on what cable TV you are subscribed to. That might work out well for folks with two houses with a roku at the 'other' house.