This is a small help to get you started with the JUD (Jabber User Directory) in
Gentoo.

You must add this to multiple.xml in the services section:

<service id="jud">
  <host>jud.localhost</host>
  <load><jud>/usr/lib/jabberd/jud.so</jud></load>
  <jud xmlns="jabber:config:jud">
    <vCard>
      <FN>Local User Directory</FN>
      <DESC>This service provides a simple user directory service.</DESC>
      <URL>http://jud.jabberstudio.org/</URL>
    </vCard>
  </jud>
</service>


And this to the browse section:

<service type="jud" jid="jud.localhost" name="Jabber User Directory">
	<ns>jabber:iq:search</ns>
	<ns>jabber:iq:register</ns>
</service>

(By know you know you have to change localhost for you FQDN).
One very important thing: even if it is the same machine the name's for the 
various services must be different, that means that there must be valid aliases 
for jud.FQDN.

If you need help with configuration you can try the Jabber Admin Mailling list:
http://mailman.jabber.org/listinfo/jadmin