There are changes afoot in Burma as regards changing money. There has long been “official” rate of exchange fixed between 6 and 8 kyat to the dollar and the black market rate, which floats, and is currently over 800 kyat to the dollar. It has not been legal for foreigners to exchange money at banks in Burma.
Recently, there have been changes in the banking laws in Burma, and banks are being allowed to open currency exchanges. So far, there is a report on Thorntree of one open in Yangon. The currency exchange does exchange at rates similar to the black market rate, not the official rate. (Will this mean they will eventually do away with the “official rate”?) Note that you still cannot exchange money at banks, but the banks are opening separate currency exchanges.