First of all, let's take a check on the word "empowerment". It is not necessarily about someone giving you power. Its more about facilitation of that process and your becoming confident in your own abilities.
What I've found, is that more often than not, as a project manager, you need to determine on your own how you will build this confidence. The project sponsor should do that, but most likely doesn't even know that is his or her role. So in general, project managers are very strong individuals that seek empowerment from many sources, but ultimately take responsiblity for themselves.
One way that I seek empowerment is to associate with other strong project managers. Next week I will be at PMI's North American Leadership Institute Meeting, an event dedicated to the more than 3,000 volunteers globally that keep the local chapters of the organization aligned strategically to the PMI plan and are dedicated to serving more than a half million members and credential holders. This is a gathering of the best and the brightest project managers in the profession. They come from many countries, all walks of life, and hold many titles ranging from CEO to business analyst. But they are all gathered to learn and share together, and find out how they can better serve the members.
Its the people that build their own confidence and take charge of their own projects and careers that are usually most successful in project management. PMI offers many tools, classes and meetings to facilitate this process.