Galata, Museo del Mare, Genoa
It's the last Museum finally built to celebrate the year of Culture 2004. There had been many problems during the restoration of this old harbour building, a man also died in a partial crash; no one payed for this death, as usual, anyway finally the museum is (almost) ready and has opened at the end of July.
I haven't been there yet, and the price (12 euros) is not so cheap, anyway it should be very nice.
Since there is plenty to see there and I know too little, I suggest you to take a look at Genova04 official site, there's an English page about the new museum here