Hidden away in the top right-hand corner of Björk's website, written in small font in the "Future Releases, Radio + TV section", it says this:
07.05.07 - New Album (tbc)
So it seems that Björk has set a tentative release date for her highly anticipated new album-- you know, the one that features collaborations with Antony, Timbaland, Lightning Bolt's Brian Chippendale, and many more. That would be May 7, a Monday-- so we assume that's the European release date.