http://www.dimdim. com/
This is a beta test phase of an open source online meeting room hosted in virtual space.
No downloads or fees are called for. You access the meeting room through your browser, sharing PowerPoint presentations, text, webcam images and the activity on your desktop computer. You can walk your guests through web pages, spreadsheets, or design documents just as if they were sitting with you. It might be fun! There is a launch video at the site.
My technical notes over the time.