web2+Yugma

Yugma is a free online desktop sharing tool. You can set up online conferences where up to 10 people can sign in from anywhere and view your presentation. Since they can see your desktop you can share a PowerPoint or demonstrate software, show some great web sites, just about anything. The program does not include voice but does have chat so you can use the chat window or use a phone call/conference call.

http://www.yugma.com/

Web2 - Elluminate