April 4th is just speculation. Valve has yet to comment on this. But in the meantime, CS:CZ is scheduled for November 11th or 12th.
Also, EB Games reports a release daate of November 27, thanksgiving. I seriously doubt this, but April of year is way to far off. From all of the information available, a post Christmas, early January release seems to be a more reasonable time frame.
But does it matter? Its going to be a great game, and I would even wait a whole more year to get it. Well, sorta of... ya get the idea.