First, Conics lists the 3200 as coming with the Sharp EA-75 worldwide power adaptor. The page for that adaptor says that it is the one that comes in the box, and works without a shape adaptor in the USA. I just wanted to make sure this is correct.
I can only speak to this first one. The plug shape in the US and Japan is the same. As long as the transformer can handle the conversion, you won't need anything to make it fit US plugs. This transformer (I'm almost certain) handles 100-220V and 50-60Hz, so it will work out of the box. As a reference, I got a 3000, and it only comes with the Japanese adapter: the plug is the same shape as the US, and will fit in a US wall socket, but the transformer only accepts 100V input, not 100-220V (US is 110).
Now, in my experience, the extra 10 volts has never been a problem. However, luckily, the 3xxx/1000 series has the same voltage and plug size as the PSP (5V power, not sure the exact plug size). I just picked up a $15 PSP charger at my local game store and it works great. I also got a $7 USB connector/charger for the PSP at Best Buy - it is a USB Y-cable, with a charger and a mini-B, so I can connect it to my PC and charge it at the same time with just 1 USB port. I also got a rechargable power extender brick. There are also car chargers, etc. Thanks to the PSP, you'll never have trouble finding power accessories for your 3200.