I found the solution.
Sometimes it helps, when you write your problem down on 'paper'.
SELECT
T.c.value('../../@Id[1]','int') AS PropertyId,
T.c.value('(CountryCode/text())[1]', 'varchar(256)') as CountryCode,
T.c.value('(Number/text())[1]', 'varchar(256)') as PhoneNumber
FROM @x.nodes('//Property/PhoneList/Phone') T(c)