According to the latest issue of Japanese gaming magazine Famitsu, the Japanese release of Super Mario Galaxy is scheduled for October 2007.
Obviously we won't be seeing a global release for this highly anticipated title therefore the actual release dates for other regions is still very much up in the air.
With an October release in Japan I think we could expect a U.S release for November and then fingers crossed a December release in Europe.
(Famitsu is an off-line publication, if anyone has the scans feel free to add them in your reply).