I went to Krakow a couple of years ago and loved it, definitely one of my favourite cities. Quite small and easy to get around - very doable in a few days as opposed to the likes of Rome and Barcelona
Has a really nice quaint Market Square with quite a few good restaurants arund it. Wawel Castle by the river is worth a visit. We stayed at this hotel below the castle
www.hotelpodwawelem.pl and the rooftop terrace provides a really nice view of the river. Sure you don't have to be a resident to go to it. Has a bar and you can eat up there - nice place to chill with a beer at the end of the day with the sun beating down on you. Accross the river is where you can find Schindler's factory which was being restored while we were there so it might be finished now.
Would recommend a walk through the Jewish Quarter. Plenty of churches around that are open. We walked to the Jewish cemetery - sounds a bit wierd I know but there were some good photographic opportunities. There was a highly controvercial balloon on a tether by the Jewish Quarter/river too.
Auschwitz and Berkenau are so close to Krakow they are a must if you can. It wasn't until we got to Berkenau just down the road that I really comprehended the scale of it. I shot in black and white at both as I felt it added more poignancy. It was mainly the inside of some of the 'houses' at Aushwitz where they didn't want you to take photo's. It was a lovely summer's day, clear blue skies with the sound of birds tweeting - felt very surreal.
Salt Mines also worth a visit, like another city when you get down there - the carvings are something else. They hold wedding receptions and Christmas Balls down there too - what a venue!!
Enjoy, I'm sure you will like it.