After thinking about de-nuctifying the world I've started to investigate creating a Pidgin (formerly Gaim) plugin to control Skype. This means you're still using a closed network, but from an open program, which makes migrating easier (and allows people to try multiple networks from the same interface).
The Skype API docs are pretty good and it looks like the API can support at least controlling status, sending and receiving text messages, and making and receiving phone calls. So in principle a Skype plugin for Pidgin is a possibility.
There are a few docs on writing libpurple plugins for Pidgin but less comprehensively - the author of the Sametime plugin or the guy working on a MySpaceIM plugin probably know exactly how it works (the MySpaceIM plugin is a Google Summer of Code project that fits in with my idea very nicely). There is a C Plugin HOWTO in the source code which should get things started. Some ideas in the Adium Skype plugin bug as well.
On the way I read Silver Needle in the Skype which is an article on reverse-engineering Skype and using it - very interesting tech reading... but a shame they haven't made the code available
Well since it's 8 days till we leave Cape Town and head to Japan I'm not planning to actually do anything about this, but thought I'd write it up so I don't lose the links...
Update (2008-03-06): There is now an excellent implementation of a Skype Plugin for Pidgin (Adium and other lib-purple apps too) developed by Eion Robb. Development atskype4pidgin on Google code.Share on Twitter Share on Facebook