Skype GSM Gateway
If you hate paying big roaming bills while traveling but still want to use your current GSM phone number to receive/make calls (and SMS) then consider using Skype in combination with this piece of free software and a cheap USB GSM/GPRS modem.
This device (software actually) is also useful if your country is not in the Skype Online Number list. So the biggest advantage of this system is actually accepting calls on your own GSM number via Skype.
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