ok. got it.
QRegExp regExp("((([A-Za-z]{3,9}:(?:\\/\\/)?)(?:[\\-;:&=\\+\\$,\\w]+@)?[A-Za-z0-9\\.\\-]+|(?:www\\.|[\\-;:&=\\+\\$,\\w]+@)[A-Za-z0-9\\.\\-]+)((?:\\/[\\+~%\\/\\.\\w\\-]*)?\\??(?:[\\-\\+=&;%@\\.\\w]*)#?(?:[\\.\\!\\/\\\\\\w]*))?)");
QString result = myOriginalString.replace(regExp, "<a href='\\1'>\\1</a>" );
I'll leave the question/answer here for the sake of who may be interested in this.