Send email to TFS project members

One option I've found - use the "Team Members" tool (part of the TFS 2010 Power Tools).

Whilst you can't just right-click on the 'Team Members' node in Team Explorer, you can select one (or more) users, then while they are selected you can right-click and choose 'Send Email' which launches a new email (in Outlook for me) with the selected users in the 'To' field.

In case you're also considering commercial solutions, I'd suggest you to take a look at TeamCompanion.

According to their web site, "TeamCompanion connects Microsoft Outlook (...) with the Team Foundation Server. In this way it empowers various project stakeholders, particularly business ones, to work on TFS based projects, using the one tool they use for the most of their daily tasks. Easy transition between email communication and Work Item Management, with integrated Agile Project Management features, offers the unique experience of using the right tool for every project role."

Even though I never personally used it, I have some friend which are enthusiastic fans. Might be worth a try...