I spent a rather frustrating day yesterday trying to book an Exam on Prometric's Web Site yesterday, if you want to run through their Test Takers menu system you will be prompted to decide to look for IT Certifications and then coose which Vendor aligned Certification Track you are interested in - at this point it should redirect you to the appropriate page - well what you end up with is a fancy "Page not found" message.
Eventually I sucumbed to ringing the 1800 number - while I was on the line I tried one last stab and typed in www.prometric.com/citrix and it worked, it also appears to work for Cisco, so I am assuming that this "temporary" work around will work for all vendors?
Cheers,
Dave