I've been trying to install Kannel opensource gateway for sending free sms on my computer. But I never managed to make it work by reading the guide from the official website. So I'm starting over and interested in all information I can get.
Edit: Also, an example of sms sending using a php script would be appreciated.
Thanks in advance :)
I am concerned about your idea of "sending free sms on my computer".
While Kannel can be used to send SMS from your computer, you will require one of that :
A SMSC will probably charge you for the services. Using a GSM modem or Phone means you have a valid SIM, linked to a paid mobile phone plan. Either way, you will pay someone.
There are packages available for Ubuntu 12.04 here.
And here is a good tutorial on installing Kannel from source and configuring it, using a GSM modem.