[Saxon]

Unfortunately I don't know of any tutorial to do this. In fact I'm in the same boat.

As far as I can see there are two ways of doing it - but I don't know which is better.
1. Put your forums "inside" Joomla. Insert your vbulletin forums' url into a wrapper and then modify your forums skin. You're going to have to remove the top logo part of the forums, as you've already got a logo in the Joomla part.

2. Modify your vbulletin template to look like your Joomla template. It may be possible to create a left or right column in your forums and then insert Joomla modules (eg your menus) into a column. I've found this thread over at vbulletin.com where they briefly talk about it in principle... http://www.vbulletin.com/forum/showthread.php?t=163713
This second option seems the most difficult to me.

I'm therefore experimenting with option 1 - my site: http://www.survivor-online.co.uk/external/wrapper.html
However, the problem I'm getting is that whenever anyone clicks a thread link a new window is spawned.
Does anyone know how to prevent this from happening?
I want any thread or forum link to appear in the Joomla wrapper (iframe).