FreeConference.com - Free Telephone Conference Call Service
For those of us that are cheap value minded, here's a service that provides conference calling, albeit using a long distance call. But with all you can eat phone pricing we have today, who cares.
They also have a Web Desktop Sharing tool, in Beta - haven't tried it but the basic service for voice conference is great.
Some outlook integration, of which I've only used the VCS file download, but they apparently have an Outlook Add in too.
FreeConference.com - Free Telephone Conference Call Service