Recently noticed that Iotum have released a free conference calling application for the facebook social network. More information can be found here
It's currently only available to facebook users in the US and Canada but the next release will permit International conference calling to members of your social network. Throw in something like Skype Prime and you have the basis for an online consultancy. Network, refer, advise and receive payment all through the same social networking site. Potentially, the future of consulting :)