Can I use phpbb or IPB forums with xoops?
hhttp://bbpixel.com is a site dedicated to integrating these 2 forum scripts within xoops. Installing them does however, require changes to core files, so updating your xoops version core files may overwrite any changes.
There are also import data scripts for bringing existing users/posts etc.
Recently there has been a release of a modularised phpbb forum for xoops that does not change core files. Project is HERE
This is a phpbb module (using bbpixel's work as a base), properly using Xoops Groups (currently not allowed in bbpixel's port), along with bug-fixes, code cleanup, phpbb hacks, etc. The project will attempt to remove all xoops core hacks, or at least provide a module that functions *without* the hacks, and have the hacks installable separately. This is a branch from future phpbb/bbpixel releases.
This Q&A was found on XOOPS Web Application System : https://xoops.org/modules/smartfaq/faq.php?faqid=331