I need to setup an open source SMS gateway to send messages using my mobile phone via USB cable. I tried Kannel but its lack of GUI frustrated the user who is intended to admin it (not an advanced user).
If you want to use local GSM modem (or just mobile phone) you can use the following server side alternatives:
For GUI you can use the following software:
Note: Kannel is excellent platform for large scale SMS platforms but it requires certain level of understanding underlying technologies and integration layer.