Companies providing quiz services

QuizQuizQuiz
Quiz setting company with a high-powered team setting the quizzes, each with several TV appearances to their name - a good-looking client list from the financial and professional services sectors (among others).

Brainstormer
San Francisco company offering quiz services, question packs and supplies sold worldwide - very slick web site, some online quizzes and competitions to try

Century Quiz
Quiz setting company with impressive sounding client list in the entertainment and brewing sectors. Mostly product and ordering information here with a few sample quizzes

Scripts to write your own quizzes

Software to build quizzes - contact and brief product details only - I couldn't find a price so you'll have to ask

Quiz Scripts
Downloadable quiz scripts in Flash and ASP

Test and Quiz Scripts
The Perl Archive provides downloadable scripts to build and run your own online test and quizzes, some free, some priced.

JavaScript Multiple Choice Quiz Script
The title says it all