It sounds like a releatively common problem that is encountered when UTF-8 encoded characters are displayed using the ISO-8859-1 encoding. I generally see this happen when something is "cut" from a UTF-8 encoded web page and subsequently "pasted" into a form field where the page is ultimately displayed with the ISO-8859-1 encoding.
You can experiment a bit with your browser by changing the encoding used (In IE and Firefox, the setting is under the "View" pulldown menu).
If that is indeed the problem, the fix is to make sure you pages are served using the appropriate character set with the
tag where "UTF-8" is set to the appropriate character set.
Alternately, you can "convert" the UTF-8 characters after "cutting" via several free clipboard tools, or an editor with that capability, before "pasting".