I'm a co-founder/dev at PowWow. VoiceChat is going to be in the next major release. We already have system audio being ogg/vorbis'ed to you so its not a question of expertise but simply time allocation. I completely agree that whenever we have PowWow'ed, we would have a active skype session since that's much easier than chat. That's also what a alpha release is supposed to be - to gather your inputs! So if everyone agrees that Voice chat is a must have it'll definitely be there in the general release!