One requirement that always come up when a customer requests a report is that it must print (or export to PDF) onto a sheet of A4.
This is often for summary reports that rollup useful information onto one page, such as an Event's Sessions and Attendees, so that the user can take a copy with them.
The trick to this is to set the report’s page width to 8.27 inches and the height to 11.69 inches.
This tip is taken from a post on Botsikas' Blog, which I have referred to many times!
http://botsikas.blogspot.com/2008/02/sql-reporting-services-and-a4-paper.html