Here's some good resources for you for boss strats and videos:

www.tankspot.com
www.learntoraid.com
www.wowhead.com
www.wowpedia.com

The information on Wowhead and Wowpedia will vary a lot. Some bosses have full blown strats while others just have a bit of info and some comments. Some of the comments are often pretty valuable though. Sometimes the specific strat in a video just won't work for your raid, but the extra comments often suggest some alternatives that may work better. For example, the "range stack" strat on Valiona/Theralion did not work for my raid. We shifted to having the range spread out and run into melee for meteorite and the boss went from unkillable to easy-kill.

Tankspot.

I would suggest Tankspot.com. They have tutorial videos on almost all current 10/25 man content (and older as well) and provide explanations for dealing with the mechanics of each fight. There are other sites as well but Tankspot has yet to let me down.

Cool. The first video I watched from Tankspot, Valiona and Theralion, had straight-to-the-point information and didn't have any distracting (or crappy) background music. I guess I had always assumed that the site would have videos focused on the tank perspective, but it looked useful for all roles. That's what I get for assuming, I guess.

OMFGCata on youtube also have some videos that are not as detailed as tank spot but is easier to understand and is not as serious as tankspot. Videos are usually not as long and just tell you a 'cliffnotes' version of the fight.

yogscast has some really fun, entertaining and informative videos that they made primarily i think of "first look" cata encounters from the PTR. even tho they are early videos, they do a fabulous job of conveying the mechanics and outlining early strats in a way that isn't overwhelming and is eminently enjoyable to watch.

For the nuts and bolts of encounters (ie: move here, do this) i find that www.25man.com is pretty concise.

yogscast is: http://yogpod.libsyn.com/
(they have lots of hilarious minecraft stuff too)

and the youtube link is: http://www.youtube.com/user/BlueXephos#grid/user/C80AB79060523A87

I'll recommend learntoraid.com. I like the way Kina lays out the bosses' abilities and explains the strats.