Wii AC Adapter
Nintendo includes one of these with each Wii, but you can purchase another for 3,000 yen.
Wii AV Cable
Likewise, each Wii ships with one of these bundled in, but you can purchase another for the low price of 1,000 yen.
2,500 yen will get you the improved picture of S-video.
Japan prefers the D-Cable to component, but they both deliver basically the same picture quality and allow for progressive output. Pricing is set at 2,500 yen.
Wii Component Cable
Nintendo is also making a component cable available for the system, also at 2,500 yen.
SD Memory Card 512MB
This 512MB memory card is functionally equivalent to a standard SD memory card, but has the Nintendo and Wii logos. Pricing is set at 3,800 yen.
Wii LAN Adapter
The Wii has WiFi built in, but those who prefer a wired connection will want to pick up this USB LAN adapter. It's set for release some time in December at a price of 2,800 yen