Unfortunately I can’t find a suitable alternative to Skype. I use Skype for PC to PC calls, some PC to Phone calls and I have a UK phone number which rings on Skype. I can’t find a suitable, open alternative anywhere.
I considered OpenWengo, but it doesn’t work very well on Linux (neither does Skype) and I can’t connect to my OpenWengo account from another SIP client. Also, Wengo doesn’t support incoming calls yet.
Alas, I shall renew my service with Skype for another year. Hopefully in a year’s time I’ll be able to switch to an open-source, standards compliant alternative. Bah.