You must already have DirecTV service to get DirecTV everywhere - in which case there would be several national channels you can get off the internet. If your asking can you just have a streaming account, the answer would be no.
I hope this was what you were asking.
You can just get NFL Sunday Ticket and view on your computer without having a regular directv account.
All above are correct, but just to add one thing. DirecTV 'everywhere' is confusing some people. You have to be in range of your DirecTV system (in which case you'd have a dish), so as well as others the answer is no. Sorry.