After upgrading to Ubuntu 11 (Natty) I did some further research on VoIP clients (SIP) for Ubuntu Linux as XLite seems horribly out of date now.

I came across QuteCom (formerly WengoPhone) and from first testing it seems to work quite well. The install is easy as it’s part of the Ubuntu Community Software (Universe) and that means it can be installed via apt-get, Software Center or Synaptic.