How do I assign an entire Active Directory group security access in SQL Server 2008?

I would like to use integrated security with my internal application which is all on a domain. Unfortunately, I've never been able to get this to work well. I would like to assign an entire Exchange (Active Directory) Group a role in SQL Server for read/write access to certain tables. That way I wouldn't have to create an operator whenever someone is hired or delete an operator whenever someone is fired. Is this possible? What steps would I take to do this?