I am trying to find a module or a standalone solution that I can turn into a module that will allow me to have an instant messaging system like Facebook does on a Drupal site that I am working on. I have never setup a chat system before.

My particular requirements are rather stringent. It needs to be a solution where we host the chatting server (if one is needed separate from the website itself). It must use the site's login state (can't use an external system at all, that means no GTalk, Yahoo IM, or AIM). It also must be able to handle up to 1,000 users at any given time.

I have looked through the Drupal community and I tried the DXMPP module, but it requires Jquery UI 1.8 and that doesn't work with all of the other things that my site uses (such as Homebox). We do have a Jabber server already setup and ready to go.

Does anyone have any thoughts or options here? Thanks!

EDIT: We are using Drupal 6.