Got a Google+ account? Using Google Hangouts, you can set up a video call for up to nine people for free. Participants do not need to be in your Circles to hop on a call, but they must have a Gmail address, along with Google's plug-in, available for Windows, Mac and Linux. Android or iOS users need to install the Google+ app on their phones.
During the call, you can upload and share your Google docs and edit collaboratively while you're at it. To increase the number of participants beyond nine, you can try Google Apps for Business for 30 days for free, and $5 a month per user after that. If you'd rather not look at your colleagues' mugs on a call, Google Talk is a handy voice-only tool with file sharing, IM and Gmail integration. On the desktop side, although Google Talk works on Windows machines only, smartphone users are good to go; iPhone users need to install Vtok to join in the fun.