As posted, NASA provides a site with many regional webcasts and the championship webcast (here). Historically, Team 108's SOAP (Sigmacat Opponent Analysis Program) website has also been a good resource for match videos.

Usually, threads for each individual regional will pop up throughout the season (such as the Chesapeake Regional discussion found here ). From these threads, some teams may choose to post links to scouting videos hosted on individual team sites. Hope this helps.