- Right click on the PDFCreator printer in the Control Panel.
- Go to General tab -> Printing Preferences button -> Advanced button
- Change Paper Size from A4 to Letter.
- These are Windows-based settings. You may need to follow previous posts' advice about setting the page size within PDFCreator's options.
Source: http://forums.pdfforge.org/discussion/4700/pdfcreat-ppd-changing-a4-default/p1