Czech.cz
We are not sure how up-to-date the information is, but this page gives you the locations of ATM machines in Prague.
http://www.czech.cz/index.php?section=1&menu=125

Jason Cholt.com
Report lost or stolen credit cards on these numbers.
http://www.jasoncholt.com/prague/prahainfo.html#2

Prague Experience
Advice on local money matters: currency, credit cards, ATMs, currency exchanges, banks and lost or stolen credit cards.
http://www.pragueexperience.com/information/tourist_information.htm

World Executive
Contains pictures of the local notes and coins, to help you familiarize yourself with the local currency and spot fakes.
http://www.worldexecutive.com/cityguides/prague/currency.html