Skype Takes on the Enterprise
Larry Dignan (ZDNet) submits:
Skype on Monday announced a beta that will allow it to connect to corporate telephone networks across the globe.
Technically, Skype’s beta is dubbed Skype For SIP for Business users (statement, Skype blog, Techmeme). SIP stands for Session Initiation Protocol, which is a standard for voice over Internet protocol used it corporate networks. Simply put, Skype will now connect to corporate phone systems 
so you can Skype fixed line phones and mobiles from a traditional PBX system—your standard phone set-up.