It has recently been announced by phpBB that they will be dropping support for phpBB 2 in October this year. This coincides with PHP's drop of support for PHP 4 in favor of 5.
Edit: After rereading the announcement, the previous statement is not quite correct. phpBB will only be removing the download links for 2.0.x from their site in October. The official date for end of life is January 1, 2009.
Currently, our board uses phpBB 2 and I have been working on a phpBB 3 install off and on for the past several months (since the the Gold release was made). Since phpBB will be dropping support for version 2, I will be putting more time into the version 3 board instead of updating and installing new MODs on this board. I currently have a live test set up, and if you want to play around on it, feel free. You can find it at http://clantitan.org/forum2. Keep in mind that the database is currently an old on (from May 2007, IIRC) and that it may sporadically go down, be wiped, changed, etc as I install the MODs which will be present when I finally take it live.