This is a new resource that you can check out at http://www.dimdim.com. It allows you to do online webinars on their server or yours. Just added desktop sharing as well. You can record these as well and use them later. Great for businesses. Has a free open source version, while the pro is only $99.
Differences are in what you can do with them (a few other features) and the number of attendees. It's about $100 per year per 20 people with the pro version.
