Today I was surprised to see that skype is not working. Recent updates to the skype client has killed skype's supernodes. Making it hard to sign in and relay VOIP traffic. That forced me to investigate alternatives.
I have heard good things about google talk, but never bothered using it. I thought it might be a good time to try it out. Being a linux-KDE user, I was initially dismayed to see that google does not have a talk client of my platform. After a bit of googling, I learned that I could have google chat running on Kopote. I followed the instructions, but was disappointed that I could not do voice on it. I also learned that on KDE 4.5 Kopote supports voice on google talk. Also learned the Gnome guys have it easy with the Empathy chat client.
Further investigations led me to what is probably the easiest way of using the google talk service. If one fiddles about with the chat option in gmail on the browser, you will find you can do voice and chat. But, you have to install the a plug-in. I just did that, tried it out and the quality is quit decent. Not as good a skype though and I occasional get a funny chirp sound while talking.