Hi,
What you can do from outlook is that I can create a meeting request and setup a meeting workspace and invite attendees from there.
I have done that a few times for meetings, so I have made a Meeting request in outlook and then chosed to create a meeting workspace site in sharepoint, works perfect.
What I've also have done in my Outlook client is that I have linked the Events list in Sharepoint to be displayed as a calendar in my Outlook client. However I can not update the Events calendar from my outlook client since it is just a read only view of the events list. And I have not found any way that comes out-of-the-box that will allow you to update the sharepoint events list, that is be default not possible.
But It would be nice to be able to do updates from both sides, definately something that is worth checking out and hopefully that kind of functionality will be in future versions.
Regards,
Thomas