Okay so I found some great info on this site about presence aware stuff:
       http://blogs.msdn.com/modonovan/archive/2005/05/11/416376.aspx

Now, this site exposes a sample CAML for the schema.xml file for a particular list web part...  However if you decifer this a bit you will get to the core html for the presence aware feature:

<table>
<tr>
<td>
<table cellpadding="0" cellspacing="0"><tr><td style="padding-right: 3px;"><img border="0" valign="middle" height="16" width="16" src="/_layouts/images/blank.gif" onload="IMNRC('a@b.c')" ShowOfflinePawn=1><td></tr></table>
</td>
<td>
<a href="mailto: a@b.c"> name</a>
</td>
</tr>
</table>

 This presence aware html code will allow users to check for an outlook schedule, go to a my site, or see if the target user is online(Microsoft Communicator)...  This is a really great feature and its so simple...  In your web parts just display render the html to the screen and substitute in an email address and a name.  I'm going to use this to make Account Managers presence aware on their clients sites, and when an user search for a client, the results will include the account managers for the client and they will be presence aware.  It really is an exciting feature for the clients, they get very excited about it.  So test this out on your sharepoint deployment and let me know how you might take advantage of it.