peppolone

Plugin used to display the most recent topics of your phpBB forum(it works with phpbb 2.* and also phpbb 3.*) 
You can set the number of topics to display, wrap long words or exclude a category of the forum. 
<a href="http://www.4mj.it/wordpress-phpbb-last-topics-plugin/" title="Phpbb Last Topics" rel="nofollow ugc">Plugin Homepage</a>

WP-Phpbb Last Topics

Plugin used to display the most recent topics of your phpBB forum(it works with phpbb 2.* and also phpbb 3.*)

skipstorm

This plugins adds a widget with the latest posts from your phpbb3 forum. 
To make it work you have to add a file on your forum directory wich is easily configurable to fetch the posts from a specific category or the whole forum. 
This plugins supports multiple istances so you can display topics from different forums or categories in multiple widgets.

Sk Latest Post Widget

This plugins adds a widget with the latest posts from your forum.

WP-Phpbb Last Topics vs Sk Latest Post Widget