Virtual meetings work very well for our small non-profit (New Media Arts, Inc.) and its projects, primarily for reporting on projects to each other and doing group planning in Talk. We use both Second Life and Kitely, depending on the project. We use emails and forums and GTalk to set the meetings up.
For a group larger than four, Skype doesn't work well, and if people aren't familiar with each other's voices, we need the visual cue of seeing the little green flashies over our heads. To keep some of the chaos under control we've instituted some
conventions, such as arranging our meeting chairs in a circle so we can
talk in turn, moderated by the leader of whatever project we're working
on. We use mostly Talk, but also text Chat and occasional notecard passing to keep communications straight. No one cares what form our avatars take, and we make sure to have
Tiny seats available, at least in the SL grid. Since our business is arts in virtual worlds and other internet platforms we obviously need to be there to execute our projects, but it works well for admin as well.
I agree on the tech difficulties, especially with invitees who haven't been inworld often, or at all. Meetings have to be scheduled ahead, and the participants have to budget enough time to load whatever software they need to get inworld to be on time. It's a short commute, but still a commute. Our typical meetings have participants from all of the US & Canada continental time zones, Australia, GMT and CEST - tech issues aren't the killer, finding mutually acceptable times is.