Have to agree with Pawel.Poznan is quite central to many tracks,Leszno,ZG,Gorzow,Pila,Ostrow,Rawicz,Gneizno,Wroclaw,Torun and Bydgoszcz,all within a train rides distance.With the exchange rate around 4.30 zl=£1,you can't go wrong.A good link on sightseeing,eating and drinking,getting around can be found at:- http://www.inyourpocket.com/
Been 3 times myself in the last year,and can highly recommend a weekend in Polska.If I could go every week for a speedway meeting over there,I would!