General: - blues in Poland
PSB - Polish Blues Association
blues24 - polish online radio, blues around the clock

Polish artists:
Bart Łęczycki - one of the best Polish harp players
Paweł Szymański - acoustic blues
Easy Street - country blues duo

Other artists:
Rory Block - a great voice, excellent guitar playing, beautiful and expressive interpretations of pre-war country blues classics
Willie Salomon - authentic old-style blues from... Bavaria! Highly recommended!

Rawa Blues - the biggest Polish blues festival
Olsztyńskie Noce Bluesowe - the most interessting Polish blues festival

C.F. Martin
Gibson Acoustisc
National Resophonic
Vintage Info - Martin
Vintage Info - Gibson
Vintage Info - National
American Guitar Shop - fantastic guitar shop in Berlin