Download this mod
THIS MOD IS DEPRECATED, AND REPLACED WITH AEVA.
Download from: http://aeva.noisen.com/download/
For current users, it is recommended to upgrade to Aeva or Aeva Media. Check its package file to find a conversion script inside it (aeva_convert_old_bbcodes.php). It also converts tags from many other older mods such as [ytplaylist] or Google Video BBCode, etc.
Just extract the conversion script via FTP to your directory where SMF runs from. Put your forum in maintenance mode, and then point to it in your browser.