Here's brief information about the system in Thailand

    ATM
        Plus, Star and Cirrus system cards work. It is also possible to get
        money from Visa, MC, AmEx, JCB, Diners at exchange booths and banks
        with a fee.

    Credit Cards
        Visa, MC, AmEx, JCB, DC at most of the large retail establishments,
        restaurants, hotels and travel agents. A surcharge of between 3 and
        5 percent (sometimes more) is almost universally applied.

    Traveler's Cheques
        There is a fee (7 Baht per cheque) and a tax (3 Baht per cheque).
        Money exchange booths with competitive rates are open at all
        hours, everywhere.

    Change money
        Money exchange booths with competitive rates are open at all
        hours, everywhere. Every major currency is accepted. Most will
        not exchange Baht for other currencies.  Banks will, but only
        during regular banking hours. Some banks have an exchange window
        that is open at other hours.

    POSTCHEQUES
       (This info. is kindly provided by Khun Ralf Von Gunten)
       With POSTCHEQUES one can get money in every post office. With one
       POSTCHEQUE, one can get up to 5,000 Baths, which is much enough for a
       while. I used successfully POSTCHEQUES (February 92 and July 92)
       in small places like Khun Yuam (near Mae Hong Son) and Si Chiang Mai
       (near Vientiane, Laos). All the small banks there didn't accept my
       VISA Card or something else. What's better, with POSTCHEQUES: It's
       free of any charge and the exchange rate is often more favourable.
       People who wants to use POSTCHEQUES should ask the closest post
       office.

       bobwal@casema.net pointed out that in July 1998, one can get
       POSTCHEQUES up to 8,000 Baht.