One of spaces' new features is the ability to use XMPP clients in conjunction with the normal space chat.
You can use XMPP clients to chat to other users through the in world space chat window, and they can reply back either using a XMPP client or using the normal space chat.
Any XMPP client is fine to use, but the one we use the most is Pidgin.
Download and install the client you want to use, and then follow the next steps to get it set up for use with space.