The only legitimate site I can think of to do this is TVCatchUp which you can find at http://tvcatchup.com/. You have to sign up but I did two years ago and haven't noticed any increase is Spam and there's an advert you have to watch before the chosen channel shows up but that's the way they earn their pay and it only lasts about forty seconds.
In the UK I get a choice of forty channels - obviously those you normally have to pay for aren't included in that list but it's free and it's TV. You might find your DSL/Braodband speed isn't up to the job though and if you're on a restricted download package, forget the whole scheme.
comcast/verizio/hula all have services to watch tv some are free and some are not. apple and amazon and google also have free online services for tv and movies. some paid ones now are redbox and netfilx for a small price per month you could watch your shows when they come out on downloadable dvd content.