I finished a plugin called SMF2WP for Wordpress that create a log in/out bridge for Wordpress.
Here is description:
SMF2WP is a simple one way bridge from Simple Machine Forum to Wordpress. This means, this one uses databases of SMF Forum and sync to WP database every time a user performs log-in action in both WP and SMF. To get this working, it is highly recommended that you have a fresh install of Wordpress with an install of SMF. Also, WP and SMF must be installed in same domain, and should not be being accessed through a subdomain. For example, if your website contains of Wordpress for news and SMF for forum, if your news is mydomain.com, then your forums should be somewhere like mydomain.com/forum.
This plugin will do these following tasks:
* If a user log in WP, then that user will be logged in SMF using SMF API.
* If a user logout WP, then that user will be logged out SMF using SMF API.
* If a user log in SMF, will be logged in WP as well.
* If a user log out SMF, will be loged out WP as well.
This plugin also works for user databases which is converted from Joomla 1.x version.
Since I can not post External Link, please remove the letter "@" at the link for it to work.
Demo site available. firstname.lastname@example.org/news/ch%E1%BB%A9c-nang/forum/
Look for detail here and download: wordpress.org/extend/plugins/smf2wp/
Tested with WP 2.9.2 and SMF 1.1.11