You can set settings for any report by going into the report's Design View then from the menu bar selecting File-> Page Setting-> Page. Now you can switch to Landscape orientation and pick paper size from about 20 pre-determined sizes (including Legal) as well as user defined (custom) size.
Be warned, if this report is going to be used on other PCs/Printers (not the one it was developed on) it may take a little tweaking. Different printers have different minimal borders. It's always a good idea to design forms without squeezing out every last millimeter of space.
Hope this helps!
The problem with making anything foolproof...is that fools are so darn ingenious!
All posts/responses based on Access 2003/2007