Definitely one of the best programs in the country in terms of the level of support is DC's HPAP program. It can give up to $40,000 in down payment assistance, plus up to another $4000 in closing cost help. Like most programs of this sort, it is designed for low and moderate income households. A 2-person household would qualify on a sliding scale from incomes of $41,400 up to almost $70,000. Bigger households can make more, a 1-person household can make less. You have to get counseling from one of 5 intake centers, take an 8-hour homebuyer education course, and do a little homework. It is administered by the Greater Washington Urban League. You can get more info at http://www.gwul.org
under Housing and Community Development.
If you are a District of Columbia employee, there is a program called EAHP. It gives up to $10,000 in down payment and closing cost assistance. This program is also administered by the Greater Washington Urban league. It is not income based, but you still have to do counseling and the homebuyer education class.
There is a similar program for certain union employees in the District.
DC also has a 5-year tax abatement program. Naturally it is income based. If you qualify, you will not have to pay property taxes for 5 years begining the next October 1 (it's a little quirky). In addition, it has the effect of reducing your closing costs. The 1.1% in recordation fees that you would normally pay the government, you get to keep. Plus the 1.1% in transfer fees that the seller would pay the city, can go to you instead. For anywhere in the city, a 1-person household qualifies if you make less than $56,820 a year (currently). A few areas will let you go up to $63,745 a year. Again, bigger households can make more.
DC also had a $5000 first-time homebuyer credit, given by the federal government, which expired on 12/31/11. No word yet on whether it will be extended.
There was also a DC bond program that had a $10,000 closing cost help component. This program is currently suspended.
Many lenders have programs with reduced down payments and/or closing costs. For instance, BB&T has it's CHIP program, which offers 100% financing for qualified buyers. And Wells Fargo/Prosperity Mortgage has their CDMP program, which offers 2% down payment and no mortgage insurance premiums. Hope this helps.