For users of PCI/PCI-e GSM-boards Polygator under IP-PBX Asterisk it is possible to use SIP/Simple protocol for SMS messaging.
The SIP/Simple implements instant messaging via SIP.
The Asterisk-module of GSM-board Polygator implements its SMS-features via an Asterisk dial-plan that is why there is a way to setup receiving/sending SMS via the Simple protocol.
By using this feature, it is possible to turn a smartphone or even tablet PC without GSM-module into full-featured terminal for GSM-calls and SMS.