Not much Chowhound info on Krakow, so I thought I'd add my 2 cents worth.
The food in Krakow and Malapolska (Little Poland, the region of Krakow) is exotic, but at the same time reminds me of the food I grew up with; my grandmother had a deli in Brooklyn, and now I know the roots of all that food from my youth!
It took us at least a week into our trip to have a bad meal, and the prices are shockingly low. You really can't go wrong, so I'll limit my comments to a couple of places.
In Kazimierz, the Jewish Quarter of Krakow, past all the touristed cafes on Szeroka, walk past the front door of Klezmer Hois, through the front garden, and you'll find yourself on a busy street. Take a right and you'll quickly come across Restauracja Galicia, for Jewish cuisine. A two course meal of sauerkraut soup and brisket with two beverages (water flavored with marinated strawberries and cherries, also a cup of coffee)each set us back $4 per person including tax. A very nice place and an extremely satisfying discovery.
In Old Town, you'll run across Chlopskie Jadlo, part of a small chain of peasant-theme restaurants with rustic bench seating. If you venture into the rural areas, or go to Zakopane in the Tatras, there is no need to go here as everywhere south of Krakow serves this kind of food... and probably better.
If you do make it to Zakopane (and I highly recommend you do), then there is a cellar restaurant directly on the corner of Krupowki (the major pedestrian street) and Galicy. The ambience is incredible, an enormous two-level structure of vaulted stone and brickwork, a big grill in the middle with its flames licking up at the food, the infamous off-kilter wailing of live Polish folk music, it's a wild scene with freshly grilled meats and delicious breads and salads. Good stuff all around.