in typo3conf/localconf.php append
$TYPO3_CONF_VARS['SYS']['exceptionalErrors'] = E_ALL ^ E_NOTICE ^ E_DEPRECATED ^ E_WARNING ^ E_USER_ERROR ^ E_USER_NOTICE ^ E_USER_WARNING ^ E_STRICT;
$TYPO3_CONF_VARS['BE']['forceCharset'] = 'utf-8';
$TYPO3_CONF_VARS['SYS']['setDBinit'] = 'SET NAMES utf8';
convert tables containing content to utf-8
ALTER TABLE pages CONVERT TO CHARACTER SET utf8;
ALTER TABLE tt_content CONVERT TO CHARACTER SET utf8;
ALTER TABLE pages_language_overlay CONVERT TO CHARACTER SET utf8;
you might need to convert others too like tt_news, tt_products, etc…
ALTER TABLE tt_news CONVERT TO CHARACTER SET utf8;
ALTER TABLE tt_products CONVERT TO CHARACTER SET utf8;
do not forget to clear cache …
Do you encounter the follosing strange behavious after: page looks ok if loaded after cache clear but special chars are displayed wrong when loaded from the cache? This can help:
ALTER TABLE cache_pages CONVERT TO CHARACTER SET utf8;