An article on Darwin magazine brushes the surface of how to build a team, and how to help a team that has experienced problems. Help for Team Efforts is a good first look at teamwork, and telltale signs of when things are going right, and when they are going wrong.
One thing I've noticed about building a team is that it's something you have to work upon regularly. If you give your team tasks to perform on a regular basis, they start to develop a sense of how to work together. And a good team can accomplish a lot more than the combination of the efforts of individuals.