From this site:
Many states have slightly different requirements. In most cases, the application and the ballot must be sent to your individual county! The links are all here. Click on your state and follow the instructions on the web-site for your home state! The deadline in some states for receiving the application is October 15th, so get on it!
Please pass this on to anyone who has a child in college or a friend with a child in college or, as I do, an ex-husband in London. And if you have a facebook page, you might want to throw the link up.