The venue for the summit that the USA is hosting for the G20 leaders to discuss the current financial problems is, according to a Whitehouse spokesperson, the National Building Museum in Washington DC, but there's still no starting time available:

MS. PERINO: The venue is set. It will be at the National Building Museum on the 15th. The night before, there will be a head of state dinner here at the White House; it will be a working dinner. And the President had identified Dan Price here at the White House and Dave McCormick at the Treasury Department to continue to work on setting up the agenda for the meeting and making sure that it's a robust one and that we make the most of everybody's time.

So I think that there will be probably two plenary sessions on the Saturday, but all of these details are still being worked out. And so we'll continue to work on the details and I'll provide them for you as soon as I have more.

http://www.whitehouse.gov/news/releases/2008/10/20081029-4.html