We don't really. Flash's RTMFP protocol is the closest but it wouldn't sufficient to implement Skype's proprietary protocol probably. Without interop with Skype it would be be a tough row to hoe. I suppose they could create some kind of gateway...
I'm also waiting for this though. Skype is one of the few native programs I run and their Linux version sucks.
What's so hard about writing it in Javascript?
http://www.vox.io/ are doing something like it - albeit they're a skype competitor.
This is a great idea. I would be a use from day one!