BMW is now taking reservations for October Factory tours. I have put in my reservation for the 1pm tour on Oct. 24th.

Here's some more info:

Tour Times and Hours of Operation
The Zentrum Museum
Open Monday - Friday from 9:30 a.m. to 5:30 p.m.
Entrance to the Zentrum is free.
Guided Factory Tours
Tours of BMW Manufacturing Co., the only BMW factory in the United States, are available leaving from the Zentrum. Tour visitors must be 12 years of age or older. No high heels (heel and sole more than two inches high), or "spike" heels (minimum of 1 inch diameter across horizontal plane), open toe, or open heel shoes are permitted. No cameras allowed in the factory. Reservations are required.
Guided tours of the factory are $5.00 US. A discount rate of $3.50 US is available for students and BMWCCA members.
Tours are available Mondays through Fridays at 9:45 a.m., 10:00 a.m., 12:45 p.m., 1:00 p.m., 2:45 p.m., and 3:00 p.m.
To schedule a Plant Tour call 1-888-TOUR-BMW (868-7269)