My current client is multi-national company, headquartered in Ottawa with offices in USA and Europe. With teams all over the globe, the conference calls and network meetings are part of the game. This usually means Microsoft Netmeeting to share the screen and teleconference bridge for voice. Netmeeting usually works quite OK - except when it does not - for no obvious reason :-).
Thanks to Yugma, there is now better alternative. Yugma is Sanskrit word meaning "the state of being in unified collaboration" and also a name of a startup, offering teleconferencing product that aspires to unify colaboration between platforms. And they mean it, because their product runs on Windows, Linux and Mac and integrates with Skype to take care of the voice portion.
The free version of the product offers teleconference up to 10 people (albeit it is unclear how that works with Skype which allows teleconference only up to 5 people), desktop sharing, desktop anotations and changing presenter during the session. The paid version in addition to accommodating larger teams (30, 50, 100 or 500 people) also allows keyboard and mouse remote access, session recording and replay, webcasts, filesharing and webinars (for the 500 version). The price of the premium service is very reasonable - the 30 user package costs about $30/month.
With products like this, I have every day less and less reasons not to switch to OS-X as main and only platform - running Windows XP and Linux in virtual machines to cover .NET and LAMP/NAMP stacks. It is coming :-)