If you are looking for downloads related to modding, your best bet is efnet. There is a great tutorial on how to use mirc and efnet located at: http://www.xbox-scene.com/articles/xbins.php
Hummm… this raises an interesting question, can the “xbox server” be emulated? If so then you could host an xbox server and people with mod chips could play on that server instead of the Microsoft one.
I have come across a couple of other things that might be able to do the same thing as xbconnect. I don't know how good they are. I am waiting to get a new drive for my xbox, when I get it I plan on checking them out.