NBC will stream the complete Summer Olympics 2012 taking place in London in July online, but you need to be a cable or satellite TV subscriber.
The good news is that you can watch all events from the 2012 Summer Olympics online and on your mobile phone. The caveat is that NBC requires that you verify that you are actually paying for cable or satellite TV service.
The verification requires that you generate a login specific to your TV service provider. Visit the NBC Olympics help page to generate your login to get this out of your way.