Currency: the Ugandan currency is the Shilling. There are approximately 2,300 UGS to 1 US dollar.As of  Wed 19/Jan/2011

Bringing cash: If you are bringing cash, US dollars should be "big head" dollars dated 2000 or later. Larger denomination notes (50s or 100s) give you a better exchange rate than 20s or below. Euros are also widely accepted at bureaux de change. Paying in US cash often gives you a cheaper rate for your hotel or tours than Shillings.

Credit and debit cards: None of the ATM machines take cards with a Mastercard logo. The whole country went Visa earlier this year so if you are depending on your Mastercard ATM or credit card, this is a major problem unless you are at some major hotel Barclay's Bank in Kampala will get you money using your Mastercard logo card for a fee. For example, a USD$400 withdrawal by your Mastercard ATM will cost you USD$25 processing fee.

ATMs: If you have a VISA ATM card then there is a wide network of ATMs that will give you money and at better rates than from the bureaux de changes. Standard Chartered is the best bet. 

If you are going to buy a gorilla permit then you have to pay in US$, Ugandan Shillings, Euro or GBP (you will be stung on the exchange rate if you don't pay in US$), this can be cash, or travellers cheques for a 1% fee. No credit cards are accepted by the UWA.