“Do you think this is just yet another toy synth?” asks Denkitribe. “I don’t think so. This is a very serious virtual analog synth.”
Looks pretty cool from the demo.

This is the E3 Trailer of Wii Music for Nintendo Wii.
Unfortunately - it looks like this is a music game with the emphasis on game.

At this morning’s Nintendo media briefing in Los Angeles, announcements included new Wii Sports, Wii Music, and the Wii Motion Plus Controller.

Remain Calm has put together a list of its top 24 music apps for the Nintendo DS:

bliptracker - a drum machine & sequencer
dsmcu - MCU-compatible mix controller
Protein[DS] - sample looper, scratcher, glitcher
nitrotracker
kaosDS - converts touchscreen data into midi over wifi
sampling keyboard
dstep v2 - a visual sequencer
glitchDS - a cellular automation sequencer
repeaterDS - stuttering sample player
midipad [...]

WiiJing is the use of Nintentdo’s Wiimote to control DJ software. This is a demonstration of Wiijing, presented by DJ ! for the website www.djwiij.com.

Tony Amendolare at ElectroKraft has introduced Super Synth Drums - an NES cartridge that runs the machine into a drum synth.
Super Synth Drums is a genuine Nintendo NES cartridge that transforms your original NES, or clone system (Yobo, Generation Nex) into an 8 bit percussion instrument. Just plug the cartridge into your Nintendo NES system [...]

The Korg DS-10, the cool new virtual synth for the Nintendo DS, is going to get worldwide distribution, according to the DS-10 blog:
Hi there! my name is Tomi from AQI Inc.and I’ll be in charge of this product for international territories. For those of you out there wondering the release of DS-10 other than Japan, [...]