After reading the email, I went to the USCIS website to check my case status online and this is what it said;
On October 2, 2009, we ordered production of your new card. Please allow 30 days for your card to be mailed to you. If we need something from you we will contact you. If you move before you receive the card, call customer service at 1-800-375-5283.This step applies to applications that result in an applicant receiving a card (such as a green card) or other document (such as a naturalization certificate, refugee travel documents or advance parole). Applications will be in this step from the time the order to produce the card/document is given until the card/document is produced and mailed to the applicant. You can expect to receive your card/document within 30 days of the approval of your application.
If you do not receive your document, please contact our National Customer Service Center at 1-800-375-5283.