Google plus is introducing new feature that allow users to make free unlimited conference calls within Hangouts.
Mr. Jarkko Oikarinen, Google staffer and also the originator of Internet Relay Chat announced that a Hangout will allow you to make free video chat with others.
But most interesting thing is that you do not need Google account to access and to join the conversation. This will not only attract more people to Google plus and also make both party lines and conference calls are conducted.
He also said that we are listening to feedbacks and we will make Hangouts better for Google plus users.

How to use:
Adding call to a Hangout room is very easy. First click “Invite” at the top of the Hangouts and then select the “Phone” on the left side of the window. After entering number you want to make call, choose “Call now.”
Currently Hangouts supports free calls for US and Canada.