/ Australian guy in Poland for 1st time
krakow(The old Town, Castle) krakow.pl/en is nice
(nearby Krakow are Wieliczka muzeum.wieliczka.pl/pl/english.html - salt mine and Auschwitz - Oświęcim - consentration camp auschwitz.org.pl/
and Wroclaw wroclaw.pl/m6843/ are nice, I have never been to Szczecin,so I dont know,
I love poilsh mountains (Tatry mountains ezakopane.pl/poland/)where you can find snow, because you can't be sure that snow will be everywhere in Poland, now is no snow but is still cold, and according to forecast in few days should be snow again.
I am from Warsaw and if you are interested in some communism time buldings ti is good place, there is huge Palace of Culture - e-warsaw.pl, castle rebuilt after war (so is not old but looks like:) and other palaces and museums. many people hate (is gray and depressing) my city but it has some atmosphere.
Have a nice time in Poland !! :) :)