Heh, well it's going to be a concern again after this month. IIRC they said they are going to release a more complete tool to let you explore the Skype network in general (besides just decoding packets for sniffing). In theory you can penetrate corporate networks wherever there is a Skype client running, and if they found a bug in an old version of Skype it's possible they could send a worm through the network and take out a lot of machines.

But maybe it is more likely that it was just an innocent bug. I just asked the question because it seemed like a big coincidence that Skype should go down right before these guys do a big exposee on the protocol and encryption.