I tried the Wengophone binary on 5.8 and got the follwing:
./qtwengophone: /usr/lib/libstdc++.so.6: version `GLIBCXX_3.4.5' not found (required by ./qtwengophone)
./qtwengophone: /usr/lib/libstdc++.so.6: version `CXXABI_1.3.1' not found (required by ./qtwengophone)
It's the same error that the latest Skype gives (older Skype works ok already).
There is a Vector cxxlibs-6.0.3-i486-1 package installed.
Is this something which is easily updated?
I posted a solution to that here: http://www.vectorlinux.com/forum2/index.php?topic=3430.msg21619#msg21619
It works fine.
Although I'm not fond of Skype's proprietary protocol, I'm having better results with it than with Gizmo or Wengo.
So I adopted a double solution:
Wengo to call landline phones, by connecting to a cheaper SIP provider (voipcheap.com), which works pretty well.
Skype for PC-to-PC calls, which (with my limited testing) seems to give me much better quality. Probably because it is apparently better behind routers/firewalls than the SIP clients.
By the way, Skype 2.0 Beta for Linux (with video support) is out, so I'll be testing that in VL in a few days, when the webcam arrives.