Two of the better known "commercial" message boards are:
- vBulletin
- Invision Power Board
It is called "The Next BBS" (or just NextBBS)
The support board for NextBBS is: http://nextbbs.com/
You can download NextBBS at: http://sourceforge.net/project/showfiles.php?group_id=121332
NextBBS is OPEN SOURCE which means it's free.
Free software is a matter of liberty not price. You should think of "free" as in "free speech".
People should have the right to use, study, copy, modify, and redistribute computer programs as this helps society grow as a whole. When people are not allowed to do the above, then it limites creativity and if you don't get to work on something you can never help make it better.
That is why a web browser like Mozilla Firefox can quickly fix bugs and Internet Explorer can't. Because they only have one company working on it, and that company is busy with other things and can't fix every bug the second it is found. But since Mozilla Firefox is open source, anyone and everyone is allowed to work on it to improve it and make it better, so bug fixes are able to be done as soon as the bug is found.
Message boards are no different. It can take forever for a message board with only one company working on it to fix their bugs, but if the message board is open source then it takes less time because anyone can patch the bug and submit the "bug fix" so it can be added to the offical download site.
NextBBS uses the GNU Public License, as most open source software uses.
Do yourself a favor, if you are going to use a message board then use the best!
http://nextbbs.com/