Michael Robertson, CEO of Gizmo5 has done it again! He has launched a cool new service called OpenSky http://gizmo5.com/opensky, a service that enables SIP-to-Skype calling. It's not the first time someone has broken the Great Wall of Skype to enable SIP-to-Skype calling, but it's always great to have a new method of accessing the popular Skype network using the standard SIP protocol.

Gizmo5's free Skype gateway called OpenSky is open to all users enabling any SIP-based VoIP software or SIP-based phone system to make calls to Skype users. What they've done is to create a SIP alias for every Skype user. So if you want to call a Skype user you simply dial [email protected] from any SIP-capable device.

The service can initiate a call by sending a SMS so any mobile phone can be used to call a Skype user or calling from a web browser using just flash. Users can even have any SIP call forwarded to their Skype address using my.gizmo5.com.

This is currently a free service Gizmo5 for calls up to 5 minutes long. For longer calls they are offering a paid service.

I can see this service being useful for when you want to make an international call and don't want to be forced to use your PC to make a free Skype-to-Skype call. Instead you can use your SIP desk phone (if it supports URI dialing) or you can use your mobile phone to initiate the call.