The Czech Republic's currency is the Czech Crown, the Koruna, abbreviated CZK. There are 20, 50, 100, 500, 1000 and 5000 Koruna bills. The international exchange rates can be found at www.xe.com .
You are allowed to import or export money up to the value of 200,000 CZK in the Czech Republic. The actual currency of the money is not important. If you plan to take more money with you this has to be declared to the Czech financial authorities.
If you need to change cash it is advisable to go to one of the main banks, such as Komerční banka, Česká spořitelna or ČSOB. They also accept traveller cheques.
Watch out for exchange offices. They can be found in every large city and in tourist regions. The exchanges rates they offer are often worse than the official rates. Additionally, you will have to pay high fees.
A widespread network of ATMs (bankomaty) is available in the Czech Republic. They will normally accept international credit cards, and their exchange rates are usually better than the ones in exchange offices. Credit Cards are also widely accepted in gas stations, hotels, restaurants and shops.