2
For $5, you can get a copy of FlashChat, an existing and very nice Flash based chat application that is already ready for installation in XOOPS (and a ton of other CMS/Portal systems).
Here's the link:
http://tufat.com/script.php?id_num=2
No, I'm not affiliated with the programmer. I'm just a happy customer. Considering how nicely it integrates with XOOPS, and how cheap it is, and how pretty full featured it is, it's hard to see why one would work on another module.
Good luck,
--Julian