We just updated to the latest Moodle version (2.8.3) in order to test the WebEx plugin found here:
https://moodle.org/plugins/view/mod_webexactivity
I created a free account with "WebEx Meetings" hoping to test out the plugin with that. Unfortunately it seems that "WebEx Meetings" is not the same as "WebEx Meeting Center" or "WebEx Training Center" which is all that particular plugin supports. After a completely unhelpful talk with WebEx support I am not really sure what the difference in these services is in terms of what they provide or what they cost. They pushed a fourth option, "WebEx Event Center" which is explicitly not supported with the plugin in question anyway.
At any rate, with no real luck regarding WebEx, I am looking for more options. I am told Adobe Connect is out because of cost. We had previously tried BigBlueButton, but had problems with lag we were unable to resolve. I found what seemed like another promising option after looking at the forums, WizIQ, however this plugin is supported only up to Moodle version 2.5 (or 2.4 according to their website).
At this point it seems there are no good services with plugins that actually function with the latest Moodle and in a last ditch attempt I figured I would see if anyone had any suggestions. Thank you.