I have no experience with Instant Web Publishing but this sounds more like a job for a cms like Drupal.
Comparison of Forum Software - http://en.wikipedia.org/wiki/Comparison_of_Internet_forum_software
Drupal - http://en.wikipedia.org/wiki/Drupal
Joomla - http://en.wikipedia.org/wiki/Joomla
List of Wikis - http://en.wikipedia.org/wiki/List_of_wikis
Google "cms vs forum vs wiki"
I would suggest starting a free wiki here - http://www.wikispaces.com/
From their front page....
What is a "wiki"?
A wiki is a space on the Web where you can share work and ideas, pictures and links, videos and media — and anything else you can think of. Wikispaces is special because we give you a visual editor and a bunch of other tools to make sharing all kinds of content as easy for students as it is for their teachers.
Their options for free and paid wikis
Another option is WikiDot