I've installed mod_webpresence on jabber.meta.net.nz. This is an ejabberd module which provides presence indicators in various formats - text, image, XML, etc.
It's not enabled by default, you have to register. In order to register you will need a jabber client that supports service discovery (eg, PSI, tkabber, and so on - pidgin doesn't appear to do this). Browse for the webpresence.jabber.meta.net.nz node, hit the register link, and follow the prompts.
For more information, read http://www.ejabberd.im/mod_webpresence