How do I get to Yichang to catch the Yangtze River cruise?

I have never been to China, this will be our first time. I will be in Guilin in April 2010 and like to take a Yangtze River Cruise. How do I get to Yichang to catch the Yangtze River cruise? Do the cruise always end in Chongqing or does it go to Xi'an? How do I get from Chongqing to Xi'an? Thank you.