Thank you very much in advance, Marleen.
In the \Other Goodies folder is a Build Booklet script as well as the source code. An updated version of the script is available from: <http://www.adobe.com/support/downloads/85f2.htm>
Here’s some information about the Build Booklet script: <http://www.adobe.com/support/techdocs/2342a.htm> For more info about the build booklet script, take a look at: <http://www.adobe.com/support/techguides/indesign/idbbscript/main.html>
You also need to have the visual basic runtime files. You can download and install them from: <http://support.microsoft.com/support/kb/articles/Q235/4/20.ASP>
A technical guide describing how to install, use and modify the build booklet script for creating impositions in Adobe InDesign 1.5 is at <http://www.adobe.com/support/techguides/indesign/idbbscript/main.html>
The build booklet script exports each page as a PDF and then places the PDFs of all the pages into a new document. The resolution of the PDFs exported can be controlled by creating a PDF export style with the right settings and then in the build booklet script selecting that style.