As if by fate, I found this article by Sriram Krishnan on The First 30 Days for a new exec in any organization. He summarized a few lessons from his experience:

1. Relax.
2. Meet everyone.
3. Make obvious people changes, quickly.
4. Build key relationships.
5. Pick a crisis or early win (and don’t mess it up)
6. Communicate (regularly).

Check out the full post here.