first, ESPN3 has to be carried by your internet provider. if you've had it before, then it is. if not, when you go to ESPN3.com it will have some message, ask who your provider is, then urge you to contact them and request they start providing ESPN3 (read: pay us).
you can go to ESPN3.com before gametime and check their schedule.
for last weeks game, i could not get the game on DTV because it was broadcast on the secondary ".2" digital channel of my local FOX affiliate, and DTV only carries the main ".1" channel. It was on Gameplan, but i wasn't paying for that. It was available on ESPN3, via AT&T (on MS Gulf Coast), and was not blacked out. I don't think ESPN3 blacks out games that are on SEC network, i think blackouts are only for cable channel broadcasts when the game is also available on a local channel.