Beijing to Guangzhou on the new high-speed rail route

How do I book tickets from Peking to Guangzhou on the new high-speed rail route? The line that opened on December 26, 2012 that runs at an average speed of 300 kilometers per hour and will cut the travel time between Peking and Guangzhou from more than 20 hours to around eight. I want to make sure I book the correct high speed line. I am not sure which train station in each of the cities to book this. Thank you.