I'm a bit late on this, but the location/dates for MAX 2007 have been announced over on Ben's blog:
MAX North America: September 30-October 3, 2007, Chicago, IL
MAX EMEA: October 2007, Barcelona, Spain
MAX Japan: November 2007, Japan
This will be my first time in Chicago (of course, I'm only going if I get asked to speak). I'd love to go to the MAX in Japan.