Czerw's in the Port Richmond section of Philly. 3rd generation Poles, make it and smoke it right there. Really old school store, best I ever had, plus nice family business. All authentic, plus tons of other old world Polish goodies. My wife and family are Polish, and they love it.
Located right off of I-95, 3370 Tilton St., Philadelphia, PA.
I waited in line a LLLOOOONNNNGGGGG time, the Thrusday before Easter to get Kielbasa from there. And it was worth it.