The Irish Mbassy is a favourite pub of many expats and British/Irish tourists in Krakow. As well as serving Irish themed drinks they have the normal Polish options too. It is slightly more expensive that the bars close by (12zl for a Zywiec), but can have a great atmosphere.When it gets busier they open up the stairs for more seating and an additional bar.
They show all major sports (Football, Rugby, Cricket etc) on one of the many TVs.
The bar is one street behind the main square, so very easy to get to.
They also do a very tasty Sunday roast dinner!