6 Signs of Good Software Project Managers: "Although they are often unappreciated by those around them, they are critical to making software development happen.  The best project managers are often the most inconspicuous since things happen so smoothly when they are involved."

I liked the list of positive activities too:

1. Manage Customer Expectations
2. Develop a Rapport with the Customer
3. Understand Where the Project Really Is
4. Increase Visibility
5. Speak the Developer’s Language
6. Know How to Say No