The SMS Server Tools 3 are under the General Public License.
/* SMS Server Tools 3 Copyright (C) 2006- Keijo Kasvi http://smstools3.kekekasvi.com/ Support: http://smstools3.kekekasvi.com/index.php?p=support Based on SMS Server Tools 2, http://www.meinemullemaus.de/ SMS Server Tools version 2 and below are Copyright (C) Stefan Frings. This program is free software unless you got it under another license directly from the author. You can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation. Either version 2 of the License, or (at your option) any later version. */
General Public License, English