Free Web Conferencing with DimDim

If you've been searching for a free web conferencing solution, you owe it to yourself to check out DimDim.  DimDim offers several versions, including the free version which supports up to 20 concurrent users. 

Per their website at dimdim.com:
Enabling people around the world to show pictures, PPTs, PDFs, screens, even video as part of their conversations with no desktop client (like Skype or Outlook) is technically very complicated and often at the mercy of the internet connection speed or the power of the CPU. Undaunted, Dimdim invested more than 15 man-years of engineering development into making complex web meetings simply work. We think you'll enjoy the fruits of their labor.

So simple anyone can use it.
Unlike other web conference products, Dimdim does not require users to install software on their computers to attend web meetings. Users can start or join meetings with just a few clicks. Dimdim is available for free so everyone - not just big companies with big budgets - can use it. And Dimdim is available as open source software so you can extend and improve it freely. Dimdim already integrates with CRM and LMS software and can be extended easily. And Dimdim is extremely flexible, available in hosted and onsite configurations and easily customizable.