From Publishers Lunch:
Next Oprah Book Club Pick Revealed on September 18

It's been almost a full year since Oprah made her most recent book club pick of The Story of Edgar Sawtelle by David Wroblewski, and according to the Newtonville Books Community Blog, #63 will be a Little, Brown trade paperback title priced at $14.99, with an announced first printing of 500,000 and ISBN # 978-0-316-08637-0.
Amazon reports differing metadata, listing the Oprah #63 pick as a $23.99 hardcover with an ISBN of 978-0-316-08636-3. Neither listing includes an approximate page count.

On Twitter, Oprah implored viewers to tune in on Friday, September 18, saying she'd "never made a selection like 'this.'"We'll leave others to the guessing game but it's worth noting that Little, Brown prices very few of its hardcover titles at $23.99, which narrows the list of potential candidates considerably to the following books published between January 2008 and August 2009:

Amigoland by Oscar Casares (August 10)
Crow Planet: Essential Wisdom from the Urban Wilderness by Lyanda Lynn Haupt (July 27)This Wicked World by Richard Lange (June 30)
Do Over! by Robin Hemley (May 11)
The Man's Book: The Essential Guide for the Modern Man by Thomas Fink (May 6)
Secrets to Happiness by Sarah Dunn (March 25)
Eat, Drink and Be From Mississippi by Nanci Kincaid (January 6)
The Book of Calamities: Five Questions About Suffering and Its Meaning by Peter Trachtenberg (August 27, 2008)
The Bible Salesman by Clyde Edgerton (August 11, 2008)
Undiscovered Country by Lin Enger (July 3, 2008)
Say You're One of them by Uwem Akpan (June 9, 2008, with trade pb published at $14.99 on July 15, 2009)

And not that it needs underscoring, but Oprah's selection will come a mere three days after The Lost Symbol's publication and four days after Ted Kennedy's memoir hits stores, adding up to a week the AP believes "could be a record-breaker for the publishing industry."
Newtonville Books Blog
AP
Amazon Listing