http://en.wikibooks.org/wiki/Polish/Polish_pronunciation ż - Hard zh. Sounds exactly the same as rz. Fairly similar to Zhivago, vision, measure, treasure, leisure, and French je suis. Soft zh. Similar to but clearly softer than ż and rz. z followed by i is pronounced just like ź. ziarno, ziemia, gałęzie ("grain", "earth", "branches") are pronounced as "źarno", "źemia", "gałęźe" (not "źiarno", "źiemia", "gałęźie").

ż - http://pl.forvo.com/word/%C5%BC/#pl (pronounced like rz) ź - http://pl.forvo.com/word/%C5%BA/#pl (pronounced like zi) rzeźnik (butcher) - http://pl.forvo.com/word/rze%C5%BAnik/#pl żubr (bison) - http://pl.forvo.com/search/%C5%BCubr/pl/ źrebie (foal) - http://pl.forvo.com/search/%C5%BArebi%C4%99/