If you're looking for an economical way to stick your toe in the waters of online conferencing, this may be the service for you.
Sign-up is free, and you can do free videoconferencing and teleconferencing for up to 20 people. Next, they have two paid levels of service for up to 100 or 1000 people simultaneuously. They're hoping to eventually take on the big players, like WebEx. Just for kicks, I also contacted their Tech Support twice, and both times they responded within 24 hours.
Hope this is helpful,
Rick Kerner