You are correct.
Starting on February 9, 2009, any pilots flying VFR within a 60 nautical miles (110 km) radius centered on the ADIZ are required to complete training about the ADIZ. This training can be completed online through a course called "Navigating the New DC ADIZ". Pilots may also complete the required training by attending a seminar offered at a Flight Standards District Office. Pilots must obtain a certificate which proves that the training has been completed. This certificate is not required to be carried with the pilot, but must be produced when requested from law enforcement or other agencies. Pilots flying IFR are not subject to this requirement. [src]
This is not a TFR, but a permanent special flight rules area. More info can be found here on flying around DC in general.
The specific rules can be found in FAR 91.161:
(a) Operations within a 60-nautical mile radius of the Washington, DC VOR/DME under visual flight rules (VFR). Except as provided under paragraph (e) of this section, no person may serve as a pilot in command or as second in command of an aircraft while flying within a 60-nautical mile radius of the DCA VOR/DME, under VFR, unless that pilot has completed Special Awareness Training and holds a certificate of training completion.
(b) Special Awareness Training. The Special Awareness Training consists of information to educate pilots about the procedures for flying in the Washington, DC area and, more generally, in other types of special use airspace. This free training is available on the FAA's Web site. Upon completion of the training, each person will need to print out a copy of the certificate of training completion.