You should be able to push xml/rss feeds straight to a mobile, there are 3rd party utils as well for the end user like http://www.mobilerss.net/ and many others which allow you to sync with your mobile the feeds you require. Since Vbulletin has a pda version then it is possible to read these forums directly if you know the url and they publish the pda/archive versions. It should be something like http://www.domain.com/archive/index.php/