Yes. There are categories which list forums. Find the general category for your forum first and then look to see if there is a subcategory for forums.
it really helps if you find the approriate category yourself! The main categories are usually overwhelmed with submissions from people like yourself that cannot find the proper category - your submission will get buried amongst the masses if you do that; and when an editor gets down to your submission, they'll only send it into the queue for a more appropriate category - but has to find it first; essentially doing the work you could do now with a bit more searching! You could save your submission goodness knows how much time by submitting properly now, rather than relying on an editor to fix the category submitted to, the title, the description (if these don't follow the submission guidelines), or the content isn't ready. So I really recommend you have a good look for where to submit your forum now, rather than submitting to a general category I help out on one or two Chats_and_Forums cats - what's the URL, I may be able to point you in the right direction
It depends on the type of forum as far as where to submit it. There are resource categories along with chats and forums in some of the topical categories and there are more in the Computer category, But forums are accepted, keep in mind they do need to be somewhat active...in dmoz's mind they need to be unique content.