According to Play.com, Mario Kart Wii is to be released in the UK on April 25, 2008. This differs from the official Nintendo release date of Q2, 2008 - giving the game an April-June release window.
A Nintendo spokesperson has informed VideoGamer.com that the retailer is merely guessing, confirming that no release date for Mario Kart Wii has been announced. Still, retailers have been known to be on the money in the past.
Information on the game has been slowly appearing from various sources, the most recent news detailing a robust online element, including 12-player online support, Mii integration, ghost data sharing and much more.
Other than Super Smash Bros. Brawl, Mario Kart Wii looks to be the most competent online-enabled title for the system. It also looks likely that it will release in Europe before the Nintendo brawler - currently without a European release date.