There are two sites I follow on Twitter that list free online video feeds (sometimes in English, some in Spanish, French, Italian and Dutch... I watch them all the same!) and that is how I managed to see the spring classics this year:
Steephill:
http://www.steephill.tv/ (twitter @steephill)
CyclingFans:
http://www.cyclingfans.com/ (twitter @cyclingfans)
Both also post pictures. Steephill, in particular, posts large format pictures that are a pleasure to look at.
I should add that Steephill also collects video clips after the stage, the last km, the last 5km, etc. Pretty nice.