Fannie Mae's intraday MBS yield is falling sharply, which means that mortgage rates will likely follow. The drop is significant, and likely is in part tied to the new Treasury plan to buy Mortgage Backed Securities.
If you've been thinking of buying, you would be wise to talk with your lender for a rate quote. A drop in rates increases your purchasing power, and with the incredible values that are on the market right now, you may find you can get a whole lot more for your dollar than you would have just a few months ago.
In other words, real estate is on sale, and mortgage money is going on sale too! That's something for which we can be thankful!