And you won't need those fancy transformers/converter the apple store will try to sell to you.
These little 220V plastic adapters are enough. For the Netherlands/Belgium/Germany/Luxembourg the ones to use are the double-round ones (top left of the picture).
You can get those 220v plastic adapters ($5 to $8 each) at your nearest travel/luggage store. I have never beed to Poland so i do not know if you can use those too.
Getting free internet is a tad difficult but not impossible. Most train stations charge fees per hour increments. In downtown areas you might get wi-fi access for a fee but seldom free.
Depending on which hotel you stay it is free. Check in advance if your hotel offer it.
I visited Europe last August and the itouch was a big help. Look out for McDonalds franchises as they offer free wifi services but in some instances you have to buy food (even a coffee or soda will suffice) to be allowed to use it (at least in Lille, France I was told I needed to buy food but in Amsterdam it was free for all regardless). I noticed certain sections of downtown Amsterdam near the Red Light district had sporadic clouds of free wifi.
In Brussels the hotel I stayed (Sheraton Airport) offered free wi-fi but only at the lobby and near their business center. In the hotel in Amsterdam I had to pay a fee for wifi but they had computers to access e-mail for free (Park Hoter near the Hard Rock Cafe).
Possible good news in Germany. If your mobile phone carrier in the US is T-mobile, you can get free wi-fi!!! Of course this was on Koln so I don't know if it applies to all Germany. I think it is because the T-mobile HQ are in that city. I didn't had T-mobile so I was screwed.
Enjoy your trip!