There are so many new features and capabilities in vSphere 5.0 that it's becoming increasingly difficult to keep up with everything. When it comes to getting a quick introduction on a new feature I've found a great resource is the VMware TechPub's Channel on YouTube. The channel contains several short videos (~3 minutes) that provide a high level overview of various features and capabilities. If you have a question about a new feature and what it does, this is a great place to start.
