At least when it comes to reading threads on a cell phone, you can use the archived pages on Chief Delphi. They are just text.
http://www.chiefdelphi.com/forums/archive/index.php/
But as for an entire, "real Internet" experience, the iPhone and iPod Touch are currently the only devices that I know of that allow you to achieve this. (Though several other smart phone companies are working on this feature as well). Every other cell phone only has a limited Internet experience, and the websites that give you more control often have to write their own cell phone applications to do so.
The only thing Brandon could do is install an iPhone or generic cell phone mod to vBulletin, to redirect all cell-phone traffic to a minimalistic version of Chief Delphi.
http://www.vbulletin.org/forum/showthread.php?t=171437
http://www.vbulletin.org/forum/showthread.php?t=151186