Varien is committed to the open source community and in that spirit we are pleased to announce Magento will be distributed under the Open Software License (OSL 3.0), an OSI-approved open source license. You can find more information about the license in our new License/Trademarks FAQ page and on the Open Source Initiative site.
We’ve also posted information on the usage of Magento trademarks. As mentioned in the FAQ, the code is free, but the Magento trademarks, service marks and logos are not. Please review the License/Trademarks FAQ if you have any questions on what are appropriate and inappropriate uses of Magento trademarks.