UTF-8 encoding (temporary) changed to ISO-8859-1

After writing by hand all the web page in an strictly standard format using UTF-8 encoding, I got surprised when I entered the site from an Internet Explorer browser. I don't know why, but this stupid program doesn't take the codification specified in XML format, what forced me to translate all the files into ISO-8859-1.

Does anybody know how can I tell the browser to use my encoding? I would really appreciate any help.