PDFCreator is licensed under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE (AGPL). This license ensures the most freedom for the users of a piece of software. The license gives you the right to use the software, read and modify the source, create derivate work and give this to your users, as long as you do not change the license and thus grant the same rights to them.
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 for free and in an unlimited way. You may also give copies to friends, distribute it on all PCs in your company and such things.
If you offer a service that uses PDFCreator, the AGPL requires that you must enable your users to get access to the source code of your service and that you grant them the same rights that you were granted. For example, if you are using PDFCreator as a back-end to convert PDFs from your web service, you must disclose the source of your service. If you plan to integrate PDFCreator into such an application, please feel free to contact us.
It is further not allowed to sell PDFCreator or to integrate it into closed source applications, due to restrictions in the pdfcmon License. This also includes installers with commercial intent (i.e. advertising wrappers). This requires further licensing.
These components are licensed on their own:
Ghostscript: GNU Affero General Public License
pdfcmon.dll: pdfforge Freeware License
iTextSharp.dll: GNU Affero General Public License