Lucky you, it is a place I have always wanted to visit !
I went two years ago, loved it.
If you are into Vodka, go to "Wodka" just off the main square, tried about 10 different vodkas for about £7. ie 70p each. Was utterly wasted.
We're in Krakow now, love the place, so much to see, tons of history, great restaurants, really friendly people and so many pretty girls!
Wasted? Sounds like money well spent.