Eight months ahead of the 2010 event, October 4-6 in Washington, D.C.

That’s crazy. Granted, for a few years now, the MPWomen Summit has been a hot ticket, by invitation only, drawing 350 women leaders in business and beyond. And a couple of men. Warren Buffett has become a regular–to the delight of this crowd. Goldman Sachs CEO Lloyd Blankfein comes opening night to hand out the Goldman Sachs-Fortune Global Women Leaders Award.

The surprising response this year may be testament to a nascent economic recovery. (Could it be?) Or perhaps the lure of D.C. (We’ve held the event out West, mainly in California, since 2003). Or the desire of high-ranking women to connect with one another. Interestingly, Silicon Valley’s top women, as I’ve written, are highly connected, but East coast women leaders, especially on Wall Street, frequently don’t even know one another.

Connectedness is more critical to success than ever before. If you’re not social-networked and partnering–even with competitors–you’ll slip behind. I like to think that we help remarkable women connect. Among the CEOs already committed to at this year’s Summit:: PepsiCo’s Indra Nooyi, DuPont’s Ellen Kullman, Avon’s Andrea Jung, ADM’s Pat Woertz, and Time Inc. Ann Moore. The Silicon Valley stars, including Facebook COO Sheryl Sandberg and Google’s Marissa Mayer, are on board. The Summit will also include U.S. Senators and top women in the Obama Administration.

Besides connecting top-to-top, these leaders also use the MPWomen community as a platform to do good. I remember, about six years ago, Disney Media Networks co-chair Anne Sweeney (who registered for the 2010 Summit this week) called me post-Summit and said, “You need to set up programs to enable us to leverage our power after we leave and get back to work.” Since then, we’ve created three very successful programs: a partnership with the U.S. State Department that brings rising-star women from developing countries to the U.S. each May to shadow MPWomen Summit participants, a science-and-math mentoring partnership with Exxon Mobil , and Most Powerful Women Entrepreneurs, in partnership with American Express .

The vitality of this MPWomen community relates too, I think, to an idea that Arianna Huffington blogged about early this month in a post about gender diversity. She quoted me on women’s “horizontal” view of power: “Women have a broader view of life and what fulfills them.” She went on in her own words:

“This horizontal view leaves many high-achieving women less obsessed with moving up the corporate ladder — always in search of a higher rank, better position, bigger job — and more focused on family concerns and the idea of doing something better for the world. For them, “advancing” means getting the chance to broaden their influence and reach — and to use this influence in socially responsible ways.”

To Huffington’s point, the theme of the 2010 Most Powerful Women Summit is “Building a Legacy.” The leaders we gather will talk about expanding their power beyond their jobs and their tenures, ideally to add value to the world. After all, isn’t this what true success is about?