Vbulletin IMHO is the best software package for running forums. It's administration is great, the user experience is great, and it scales well. However it's not free. www.vbulletin.com for more info.

The biggest obstacle in setting up a forum isn't setting up the software, its getting people to use it and contribute. You may want to to a little bit of research and find out if people are interested before you spend the time to set it all up.