Dipnote, the State Department blog, gives us the details:
Secretary of State Hillary Rodham Clinton will conduct Digital Town Hall of the Americas, a live web-based discussion, from the Dominican Republic on Friday, April 17, 2009, in anticipation of the Fifth Summit of the Americas to be held April 17-19 in Port of Spain, Trinidad and Tobago. The event will provide an opportunity for Secretary Clinton to launch a conversation with citizens from across the Western Hemisphere to discuss the Summit’s themes of securing our citizens’ future by promoting human prosperity, energy security and environmental sustainability, as well as the situation in Haiti, where she will visit and attend meetings on Thursday, April 16.
The State Department has their Social Media Hub dedicated to the Summit, which will host 34 democratically elected leaders from the Western hemisphere. Catch the webcast there on Friday and go over and get engaged with the questions in the meantime.