Quite easy...
Set your paper size (right-click, page setup) and printer information
You should by default end up with a layout that is the entire page. , so under the Layouts section, click on layout 1, then up above in Properties change the layout size to your print size (8.5x11).
CTRL-K (or preferences under Edit)
Go to Repetition and assuming your page and layout information is correct, you should now be able to set under the Layout Repetition section 1 or 2 horizontal layouts and 2 or 1 vertical layouts (dependent on portrait/landscape, etc). Set that, and then using the priorities you can configure whether or not these come out as cut stacks, or other configurations depending on how many up you are printing. Make sure if this is a front/back print that you choose your mirroring. In my experience, the "Based on driver settings" option doesn't work.
Hope that helps, good luck
Edited by Chris S. (10/13/11 06:17 PM)