First of all, you can only take money out at a bancomat. You can't make deposits. If you need to make a deposit then you have to make it to the branch teller during normal business hours.
PINs in Europe are only 4-digits long where in the USA your PIN can be 4 to 6 digits.
After you put in your PIN, you need to select the language you want. Almost every ATM gives you the option of at least Czech, English and German. Many also allow for Italian, Russian, French and Spanish.
You can always access your current account (the same as a U.S. checking account...except there are no checks). But you can't always access your savings account. At some machines you can and at others you can't.
One thing that was hard to get used to is that the machine gives you back your card first...then it dispenses your cash. The exact opposite of how it is back home. I've been told that the logic is so that people don't forget their ATM card. Every time the machine gives me my card back before my cash I always have this split second of fear that I don't have enough money in my account to cover the withdrawal.
"Pay as you talk" mobile phone plans are very popular here. Most ATMs allow you to purchase phone credits. So you can buy cell phone minutes at an ATM but you can't make a deposit.
ATMs kind of annoy me here because they give out 1000 and 2000 Kč banknotes. But most shops don't like to take large banknotes because, for some reason, Czechs don't like to make change.
Here's another thing I don't get...
Generally speaking, most people in the U.S. pay for everything with debit cards. Every place you go takes plastic so you don't need to carry cash. Yet, in the U.S., you can always find an ATM nearby.
And here, most places only accept cash. Yet, at times, you have to hunt for an ATM.
EDIT: Another thing you can't do at an ATM here...you can't transfer money between accounts. If you want to move money from your savings account to your current account then you need to do it online, in person or on the telephone.