The CC-GNU GPL adds the Creative Commons' metadata and Commons Deed to the Free Software Foundation's GNU General Public License. The license is the official FSF GPL, and includes a Portuguese translation.
To signal to others that you are using a Creative Commons license, you can use a Creative Commons logo, which links to the CC-GNU GPL. The result will look like this:

This software is licensed under the CC-GNU GPL.
Here's how the CC-GNU GPL works: A user clicking on the Creative Commons icon gets the CC-GNU GPL "Commons Deed" — a human readable version of the license. From that she can link to "Legal Code" — the full text of the GNU GPL, in English and Portuguese. And hidden in the tag is "Machine-Readable Code" — metadata — that will enables others to find your software.
Display the icon on any site you offer your software for download using the following markup:
For more information about the Free Software Foundation, visit their web page.