The FAA has just announced that the new rule extending the terms of first- and third-class medical certificates has been released. The rule took effect July 24, 2008.
The FAA says:
The purpose of the new ruling is to improve the efficiency of the medical certification program and process. It will also advance the services provided to medical certificate applicants.Here is the link to the full text of the final rule: Modification of Certain Medical Standards and Procedures and Duration of Certain Medical Certificates - Federal Register, July 24, 2008 (8 page 'pdf' file)
Third-class medical certificates for pilots under the age of 40 were previously required to be renewed every 36 months. Those pilots now have 60 months, or five years, to review their certificates.
First-class medical certificates previously lasted six months. Under the new rule, they now have to be renewed every 12 months.
There is no change in the terms for medical certificates for pilots over the age of 40.