Eclipse Communication Framework (ECF)
ECF allows you connect to others developers using the protocols XMPP, MSN, Yahoo, ECF, IRC, JMS, Zeroconf/Bonjour, and others. Upon installation, ECF creates a new perspective for the workspace called 'Communications'. To access this perspective, click on the 'Communications' button in the upper right of the workspace:
To connect to Instant Messaging (IM), click on ECF Connection icon
and select XMPPS protocol:
Fill out the Connection Wizard with your account:

A Contacts View will appear with your contacts:

To send a message click over the contact with right button:

After that, type your message on a Messages View:

To connect to IRC channel, click on ECF Connection icon
and select IRC protocol:
Fill out the Connection Wizard with IRC channel information:

A Chat IRC View will appear:

Using ECF Collaboration Group, you can provide Shared Workspaces:
To connect to ECF Collaboration Group, click on ECF Connection icon
and fill out the connection wizard:
A Collaboration View (ECF Generic) will appear:

Click with right button over a contact into ECF buddy list, and you will can share url, send file, send messages and others:
