Fannie Mae and Freddie Mac are government sponsored enterprises that help keep the mortgage market liquid by purchasing mortgages from banks & lenders; they then sell those mortgages to investors. This keeps the lending institutions from "running out of money to lend" and allows them to continue to provide financing to homebuyers like you and me. Fannie & Freddie currently cap the size of the loan they will purchase at $417,000. Part of the economic stimulus package is to increase this "conforming loan" size to $729,750. These "jumbo" loans usually draw higher interest rates, but with the passage of the law, interest rates on these larger loans are expected to decrease.
NAR forecasts that the increase in the conforming loan limit will result in:
~500,000 refinanced loans and could help reduce foreclosures by as much as 210,000
~300,000 additional home sales potentially generated
~reduced housing inventory
~home price increase by 2-3 percentage points
Additionally, part of the plan is to increase the size of FHA-backed loans to the same limit of $729,750 from a previous $362,790. FHA provides insurance on various loans and is backed by the U.S. Dept of Housing & Urban Development (HUD). The insurance on these loans allows more homeowners to purchase homes with low or no downpayment due to the decreased risk to the lender. Increasing the loan size limit on these loans will make home purchases more affordable for many.