CMS2CMS Migration Plugins: Why and How Swift phpBB to bbPress Transfer | Page 2
How to Prepare for Migration?
1. Back up your phpBB data
2. Install WP plugin bbPress
3. Set up custom URL structure for WP
4. Find FTP access details for WordPress.
5. Find FTP access details for phpBB
http://wordpress.org/plugins/cms2cms-phpbb-to-bbpress-forum-converter/