I got the same email. And that is what it says now at Amazon.com. Hope it actually comes out this time. I'll believe it when I have the set in my hands.
With this upcoming release it leads me to believe that S5 will be in the fall, S6 in the late winter/spring of '10, S7 in late summer/fall '10, and the complete series for holiday '10. This is all only if S5 sells well, although I think FOX will just bite the bullet and finish out the series at this point regardless of low sales.