There are some good reports on the DCTAG website, including a list of the 50 most attended schools for DCTAG recipients (spoiler alert -- #1 is Montgomery College). It also gives a list of in state/out of state tuition for the these 50 schools (although the data is from 2009-2010, it gives an idea of the spread).
http://osse.dc.gov/page/dctag-reports-and-transparency
We were pleasantly surprised the that application process (although quirky) went smoothly this spring and were notified of approval within a few weeks for my DC who will attend a school in the midwest in the fall.
There is also a full list of the participating schools. Other schools can be added if they meet the program requirements.
http://osse.dc.gov/publication/dctag-participating-colleges-and-universities
From the website:
DCTAG eligible colleges and universities are: all public colleges and universities throughout the US; public and private Historically Black
Colleges and Universities (HBCU's) throughout the US; all private colleges and universities in the Washington, DC metropolitan area.
Proprietary schools are not eligible. Proprietary schools are defined, by the Internal Revenue Service, as schools that are for profit.