You can now add Creative Commons license metadata to PDFs and image files, enabled by XMP (eXtensible Metadata Platform). XMP is an open, RDF/XML-based format developed by Adobe for managing metadata embedded in files.

Please see information about Creative Commons metadata in XMP, instructions for marking files with Creative Commons metadata for users of Adobe’s Creative Suite, and a “custom panel” to enhance viewing of Creative Commons metadata within Adobe apps.

We’ve also posted a related technology challenge: add XMP and Creative Commons licensing support to open source apps, including Open Office.