Here's an old PunBB 1.1.4 to SMF 1.0 beta 5 script I made, based on the SMF 1.0 beta 5 upgrade script. I've decided to post it here just in case someone finds it useful. (And I wish I'd posted it earlier, like when I made it last summer.)
And in case you haven't heard of it, the PunBB website is: www.punbb.org - I don't know if this script is in any way useful right now, as if you haven't guessed yet, I haven't used PunBB since June 2004, when I swapped from PunBB 1.1.4 to SMF.
http://www.cszen.com/punbb2smf.zip (18KB)