Here's how you can access it in Safari:
First you need to enable the Debug menu. Open Terminal (/Applications/Utilities/Terminal) and type in the following:
Code:
defaults write com.apple.Safari IncludeDebugMenu 1
Relaunch Safari, and from the Debug menu (right of Help) go to the User Agent submenu and choose "Windows MSIE 6.0". Then the site will work (or at minimum, it will load).
You should only use this for sites that need it though, otherwise you should set the user agent back to "Automatically Chosen" so that web developers know that there are Mac users out there that they should support.