I did find it interesting that Skype wrote their own UPnP implementation for this release and stopped using Microsoft's UPnP code. UPnP ("Universal Plug and Play") is one of those things you either love or hate. Consumers love it because it lets applications "just work" through their home firewall. Security folks like me usually loathe it because UPnP punches holes in firewalls (and lacks any kind of authentication whatsoever). However, it makes sense for Skype to attempt to use UPnP and, given what they wrote, it makes sense for them to write their own version and not be subject to the issues with Microsoft's version.
I'll be curious to hear what others think of the Skype 3.8 beta for Windows... given that I'm on a Mac these days, I won't be giving it a try.