array( name => text, surname => text, country => text, date => text )
1) How can I save this array to file as xml file?
Take a look at the Pear module XML::Serializer -- which also includes XML::Unserializer.
http://pear.php.net/package/XML_Serializer/
http://articles.sitepoint.com/article/xml-php-pear-xml_serializer