ejabberd has a built-in module that implements Multi-User Chat (MUC). As an alternative, you can use an external component like Mu-Conference The screenshots on this page show Multi-User Chat using:

• ejabberd SVN revision 486 2006-01-19
• Tkabber CVS 2006-01-20
• Psi unofficial build: nr-bundle 20060114052505-win32

Tkabber

Psi