I was in a similar suituation sometime back. I had a GSM modem connected to my linux box. I had to send and receive SMS via the gsm modem and do a background processing. I tried Device::Gsm to acheive this, but this fails to work on some scenarios. So i used a third party sms server tool called smsd, and i do the processing through my perl code.

Regards,

Arun Velusamy.