Like others said, you should be a bit more specific on which foreign countries you refer to. Sometimes stealth is not even needed, in several Nordic countries there's a legal concept called "Everyman's rights" that includes the right to set up camp (camp stoves are OK as well, but open fire not). Conditions apply, and vary from place to place. And regardless of the level of "stealth" needed, Leave No Trace is always a good principle to live by.

Here's a Wikipedia article on the subject. I can verify that the information regarding Finland is spot on, and the part about Sweden seems solid too (don't know the Swedish rules to the letter though). The rest, cross-check from other sources if possible.

--J