In most countries you shouldn't expect to find an ATM that will pay out in US dollars. But most ATMs will be happy to give you the local currency and bill your bank, and you bank will than convert the withdrawal to your currency.
Some ATMs will offer to do the currency conversion for you so your bank sees a transaction in USD. Usually this will give you a worse exchange rate than your bank would, but you may want to have an idea what the bank's rate is so you can judge if the machine's offer is a good deal.
Ask your bank whether the card you have is valid with international ATM networks or domestic-only. Many bank issue both kinds, sometimes under different names. US banks often want to be notified in advance before their cards are used abroad, so you'll need to talk to them anyway.
Consult guides for the particular places you're going to get advice on how difficult it is to find ATMs there in general.