Vyew is a great alternative for activists looking for an online conference system. The program runs a chat for up 10 people (additional users can be included with registration and the paid version) alongside a whiteboard space. You can use the whiteboard to upload documents, share a desktop or draw and design with the group.
-compatible with PC, Mac, Linux
-you can share documents, images, videos, mp3s, even flash files
-no installation is necessary