http://wiki.freepbx.org/display/FPG/Backup+and+Restore+Module

FreePBX → Admin → Backup and Restore

Select Enabled.

Select h264, h263p, h263 and h261. Click Apply'' to save the settings.

You can now use soft phone applications such as CouterPath's free 'X-Lite' application to make video calls to other Asterisk extensions.