PDFCreator is licensed under the terms of the GNU GENERAL PUBLIC LICENSE. But PDFCreator also bundles other components, that can have other licenses. In General: If you only want to use PDFCreator at home, in your business or anywhere else, you may do it freely and in an unlimited way. You may also gives copies to friends, distribute it on all PCs in your company and such things.
It is not allowed to sell PDFCreator or to integrate it into closed source applications. If you plan to integrate PDFCreator into such an application, please feel free to contact us.
These components are licensed on their own:
Ghostscript: GNU General Public License
pdfforge.dll: FairPlay License