http://www.answers.com/dour

Being me I already pronounced it the 'correct' way but I did love this note at the bottom:

"USAGE NOTE The word dour, which is etymologically related to duress and endure, traditionally rhymes with tour. The variant pronunciation that rhymes with sour is, however, widely used and must be considered acceptable. In a recent survey, 65 percent of the Usage Panel preferred the traditional pronunciation, and 33 percent preferred the variant."

What the fuck is a 'Usage Panel'? :-D