http://uk.wii.ign.com/articles/850/850297p1.html
reading between the lines and the lack of an offical comment - it seems like a cock up rather than an omission. Wouldn't be too suprised if there's a recall of some kind.
http://ph.answers.yahoo.com/question/index?qid=20080206013151AAVsIAd
Judging by these Yahoo questions it seems like the UK version has online play.