[NickGrass]

Last.fm is really useful in these cases.
Czesław Śpiewa (tough I've found his album under the name of Tesco Value) is the first that comes to my mind.
And of course, Gaba Kulka/Gabriela Kulka/Kulka & Kucz.

There's also Julia Marcell. She's great ("Billy Elliot"!!!!!!!!!!), but she sings in english.