Microsoft recently put their MIX 11 videos online. There are enough talks here to last a year. I definately recommend going to the page and scanning through their list of titles and watching whatever ones apply to your line of work. Most of them are useful, they’re not all Microsoft product plugs like How to Tailor Your Site for Bing and Migrating Applications from iPhone to Windows Phone 7.
A quick scan of their titles sorted by view count, showed the below videos.