For those who fly around Washington DC, this is old news but for others who may be traveling in to the area may need to know this so as to not get caught out.
Effective February 9 2009 Any pilot who flies VFR within 60 nautical miles of the Washington, D.C., VOR/DME must complete the FAA’s one-time special awareness training online course or seminar by Feb. 9, 2009.
The FAA decided to make the awareness training area coincide with the 60-nm speed ring surrounding the ADIZ. The area actually extends 30 nm beyond the ADIZ. While the training area does not yet appear on sectional charts, the FAA has said that it will chart the airspace, along with a notation explaining that the training is needed to fly in that area.
Pilots can complete the training by taking a one-and-a-half-hour online course
FAASTeam - FAA Safety Team - Learning Center Courses - Course Catalog ("Navigating the New DC ADIZ").
Pilots must keep proof that they’ve taken the course. A certificate of completion can be printed online for recordkeeping purposes.
The pilot will not need to carry the certificate in the aircraft but must be able to produce it within a reasonable amount of time if asked by a local law enforcement officer, FAA inspector, or Transportation Security Administration agent.