This plugin by Normen Hansen is based on a modified phpbb import PHP script for bbpress 0.7.3. It uses its own version of bbpress to convert from the initial 0.7.3 bbpress db format to a buddypress compatible one.
Features:
Import boards and users from SMF 1.1x forums to BuddyPress (forums) / WordPress (users)
Preserves current WordPress users if name exists
Create groups for forums after import (optional)
Main plugin adds admin panel for all functions
Separate plugin successively converts the sha-1 encoded passwords from SMF on user login
Includes php script that can be put into old forum directory for redirection to new topic locations
Author homepage: www.bitwaves.de