Last Friday for many was a "SNOW" day. It was the day that Apple launched their updated (and from my testing) better Operating System. It's smaller, faster and does many things better. In my testing of major Voice applications I found a few things out rather quickly:
Good News Department:
Skype 3.8 works fine
Gizmo5's latest build works fine
SightSpeed's latest build works fine
Bad News Department
Neither of Counterpath's VoIP clients work. That means neither Eyebeam nor the new and sleek X-Lite Beta work at all. Eyebeam loads up and dials, but crashes. X-Lite just crashes and burns. The Snow Leopard Compatibility Wiki also reports that the regular X-Lite has problems also. This makes this the second time in memory that when Apple has upgraded their OS that CounterPath software failed. The last time the OS changes impacted everyone in the SIP space, but it seems this time only the market's largest was caught up in it, possibly because Apple released earlier than expected. In the EyeBeam forum there was a comment about a new build coming, but as of today, Monday the 31st in London, it's still not available.
So here's my advice.
If you really need to talk, the Gizmo client allows you to add a secondary account to your login. That makes it possible for you to make and receive calls using your regular SIP accounts from your company or your telephony provider as long as you have your SIP credentials. Of course you also have to sign up for Gizmo, but that's free as is the application.