Any suggestion on a budget hotel in Beijing of best location?

We are group of 8. We'll be arriving on April 8, 2011 12:00 midnight. Can you give us an itinerary april 8, 9, 10 (we need to be on the airport by 10:30 pm coz we'll be departing on april 11 1 AM). any suggestion for a budget hotel and the best location, convenient to the places we'll be visiting.