Facebook has recently released new feature called facebook group chat which allows you chat with multiple friends at the same time, this way you can now chat with two or more friends under facebook chat and you can keep on adding more people as you wish, and other thing is that you can also chat with all the members in a facebook group who are online.
Below is step by step procedure and video on how to do facebook group based chat with your friends. As the group chat feature is rolled to all facebook users you should find it under your facebook account.
Login to facebook.com using your facebook account username and password
Chat With Facebook Group Members
Once you are logged in you can navigate to any facebook group to do facebook chat with its members as shown in the image below.
Please note that if you want to see this option on chat with group, then you first need to come online on facebook chat.
Chat With Multiple Friends
Similarly you can start a chat with one friend and then add more friends to the same chat and convert it into a group chat as shown in the image below.
You can also watch the video below to see how to do facebook video chat.