For several years, first time DC home buyers have been eligible for a $5000 tax credit.

With the recent passage of the 2008 Economic Stablization Package signed last week by Congress & the President, this provision is extended until the end of 2009. You can see this on page 14 of this “Economic Stabilization Act of 2008” Senate summary document.

There is also more information on this First-Time Homebuyer Individual Income Tax Credit program at the DC tax webpage.

This credit is in addition to the Federal $7500 credit which was part of the Federal Finance Housing Regulatory Reform Act of 2008 in June 2008, although this expires on July 1, 2009.
There are also changes in how the city of DC will treat Vacant property, but I've got to get more details on this. It is good