To add some though to the topic. I think the ultimate solution wouldn't be to port these apps, but to write an OSS x-platform alternative. The most difficult part would be how to collect royalties as the app itself must be free as in beer to be able to compete with others. We all know that maintanance and labour doesn't come free.
It would need to be:
1) cross-platform (it has to run on virtually anything)
2) OSS and free as in beer
3) low demand on system and bandwidth with best posible sound quality for speech
4) clan/guild chat/voice, kind of like teamspeak.
5) maybe some additional features

With these features it would be very popullar.
Though I don't think a single person could achive this without a company or lage sum of money behind him.