For software my personal choice is
vBulletin, once you've installed the standard forum there's a wealth of mods for it at
http://www.vbulletin.org/, of special note is
http://www.vbulletin.org/forum/showthread.php?t=132482
If you are after making the forum as search engine friendly as possible then
http://www.vbseo.com/ may be worth a look.
An alternative to vBulletin is
IPB along with various free offerings.
Both vBulletin and IPB use PHP and MySQL, I can't think of any ASP based forums off the top of my head but they do exist.
Once you've chosen your software, skin it to make it unique rather than leaving it in the stock skin. If nothing else skinning it makes it look like you care.
You'll need to create the forums and then the hard part starts, getting people to post! If you can find knowledgeable people willing to write posts and answer them then you'll have an active forum which may encourage people to join in. Maybe run competitions, or give active members some incentive.
If you can't get people posting the forum will die.