Skype For Asterisk Single Channel
for $66.00 USD each. According to the description:
Skype For Asterisk is an add-on channel driver for Asterisk based systems. Adding Skype for Asterisk to any Asterisk server enables complete access to the Skype network, including low cost PSTN access and free calling to over 440+ million Skype users.
It can be bought at their store here.
We are pleased to announce the open beta of Skype For Asterisk is ready to begin and we look forward to you participation. To obtain your copy of the software, please visit Digium's web store and purchase (for zero dollars) the Skype For Asterisk product... The beta version of software and license keys will only be available for download through August 7th. License keys will expire on August 31st.
1.79 x 10^12 furlongs per fortnight -- it's not just a good idea, it's the law!