The software included in the package is licensed under several different agreements.

MIT License:

http://www.opensource.org/licenses/mit-license.php

LGPL:

http://www.opensource.org/licenses/lgpl-2.1.php

GPL:

http://www.opensource.org/licenses/gpl-2.0.php

You can develop commercial applications and redistribute the code in this package.You only need to obtain a commercial license if you wish to make changes to Mono orif you are using Mono as an embedded runtime into your application.

Contact contact@xamarin.com if you think you need a license.