Nice hardcore band; here is some of polish -
http://www.independent.pl/1125/mult.htm - Band is called 1125, just download mp3 from the site...
EDIT:
http://www.pneuma.kdm.pl/media.htm - here you can download some of Pneuma songs. My friends like them, I don't. It's Polish too (That's why I put it here).
http://www.frontsiderocks.com/index2.php - good Polish Thrash/Hardcore band - in the "infection" cat you can find some mp3