
Tomorrow's inaguration of US President Barack Obama promises to be a huge online video event, with numerous sites offering live feeds (compiled at GigaOm). All the major subscription-based mobile TV providers (e.g., VCast) will offer it too.
You'll be able to watch it from the TV/cable broadcast feed on your mobile device if you have the SlingPlayer for your smartphone.
Upstream TV will also be offering an iPhone stream. But to get the app/client, which is currently in private beta, you'll have to email the company. However it's probably too late for tomorrow. (Update: Upstream TV has now released its iPhone app for the inauguration.)
There's no question video on mobile devices will be a huge phenomenon. You're just not going to get many users to pay for a dedicated mobile TV subscription.