Universal Music

Universal Music's Songs For Japan charity comp features more big-ass names one could hope for : John Lennon, U2, Lady Gaga, Bruce Springsteen, R.E.M., Bob Dylan, Madonna, Beyoncé, Rihanna, Nicki Minaj, Justin Timberlake... I know this kind of big charity project doesn't go well with subtlelty and in these times every donation helps, but I find songs like Cee Lo Green's "It's OK" and Pink's "Sober" quite out of place. Proceeds go to the Japanese Red Cross.

Antiopic

Antiopic release another all-star comp featuring Fennesz, Prefuse 73, The Ex, Zeena Parkins, Sylvain Chauveau, Oneohtrix Point Never... Available from Thrill Jockey's download shop Fina. Proceeds will go to Civic Force.

For Nihon

Unseen Music are releasing this big compilation with contributions from Alva Noto, Ryuichi Sakamoto, Taylor Deupree, Robin Guthrie and many more ambient / pop / electronica artists. Available directly from the label as a digital release (mp3/flac) and as a CD (temporarily out of stock, to be repressed in September) or from iTunes and emusic  Proceeds will go to the Japan Eartquake Relief Fund.
For Nihon - compilation sampler to benefit the Japan earthquake by Keith Kenniff - Helios

Chad VanGaalen

Chad VanGaalen’s "Your Tan Looks Supernatural" EP is composed of outtakes from his upcoming album Diaper Island. Exclusively available on Bandcamp as a response to the crisis in Japan, 100% of all proceeds from the EP will be forwarded to the Red Cross Aid Effort.

Snuff Crew

Get ready to sweat for good ! The enigmatic "two-person collective" (!) Snuff Crew rounded up Laurent Garnier, Hard Ton, Patrick Pulsinger and 42 other artists to contribute to techno charity comp Snuff Trax for Japan, out on March 23. Proceeds will go to the Red Cross tsunami relief fund. Available from Juno Download, What People Play, Zero Inch.

Mushrooms Project

Italian cosmic disco duo Mushrooms Project have released "For Japan", a Juno-exclusive track in support to the UNICEF Japan Emergency Appeal. 

Mamerico

Japanese band Mamerico will send benefits from download sales of their new track "A Border" to the Japanese Red Cross. (tips on ordering from Ototoy here)

Motomitsu

Music can help raise funds for relief, but it can also help people by easing their fears and anguish, even if it's only for a few minutes. In this perspective, Japanese producer Motomitsu made his house track Water Sun Rise (which he had just released before the earthquake) downloadable for free. Links for donation here.

Punk 4 Japan

A compilation spread out in two volumes for a total of 83 tracks. Now's your chance to discover music by Bob Killed A Dinosaur, Surgery Without Research, Public Disgrace, The Randy Jerkoffs and friends. Available here. Proceeds go to the British Red Cross Disaster Relief Fund.

A collection box / 11th March 2011

Pray for JP contributors Ametsub, aus and Yuri Miyauchi team up again with this collection of soothing electronica pieces out on Bandcamp. Proceeds go to the Japanese Red Cross.

Heartbeats

Get an invigorating shot of heavy bass and beats with this generous compilation available through Bandcamp. I'm no expert about dance music so I could only recognize big names like Klaxons and Steve Aoki, but in all honesty the whole selection is really solid ! Proceeds go to the Japanese Red Cross.

LIFETONES

Ringtone label LIFETONES released Pray for JP, a charity album with contributions from Ametsub, itoken, Minotaur Shock, Lullatone, I Am Robot And Proud and more. Proceeds go to Japanese NPO Civic Force. Available through Bandcamp.

toe

Post-rock band toe has released new song "Ordinary Days" (scroll down for a Youtube preview) on iTunes and Ototoy. Proceeds will go to either Japan Platform or Save the Children.

Nihon Kizuna

Over 80 international artists (among whom Kode9, Onra, Daisuke Tanabe, Machinedrum...) have donated music for the Nihon Kizuna and Nihon Kizuna Bonus compilations in aid of the Japan disaster relief effort. All proceeds will be given to the Japanese Red Cross directly. 
Read the whole press release here and download the compilation through Bandcamp and iTunes.

Zac Bentz

Japanese music writer Zac Bentz has released two albums under the Dirty Knobs and The Surfactants aliases, and is donating the profits from their sales to ShelterBox until March 19th. Download the 8-hour long drone album Field Recordings from the Edge of Hell and Diminishing Returns an electro-rock album somewhere in between Polysics and Faith No More, both available through Bandcamp.

Lullatone

Pajama-pop masters Lullatone are offering listeners to download their whole catalog and name their price. Proceeds will go to the Japanese Red Cross. With a total of 13 albums and EPs graced with titles such as The Bedtime Beat and Little Songs About Raindrops, this has to be one of the most adorable ways to donate. DRM-free, multiformat download available through Lullatone's Bandcamp page.

SXSW

After raising more than $ 125,000, SXSW released a charity compilation on Amazon's mp3 store, featuring artists such as Ben Folds, Ozomatli, Hanson (wow, didn't know these guys were still around). Proceeds go to the American Red Cross.

Play for Japan

On the initiative of guitarist Jinichiro Iida – from Tzadik-famed band Limited Express (has gone ?) – download platform Ototoy just released a massive six-volume compilation featuring 112 tracks by artists such as African Head Charge, MONO, Haruomi Hosono (YMO), Audio Active, DODDODO... Proceeds will go to the Japanese Red Cross. Tracks are DRM-free, encoded in 192 kbps mp3 format, and sold only as 18-19 track albums for the price of 1000 JPY (around $12).

The Ototoy website is only in Japanese, but explanations regarding the purchase process follow after the jump.

TONOFON

Download exclusive tracks by toy-pop wizard Shugo Tokumaru and folk-pop band Ohshu from this Bandcamp page.

Shinji Masuko (DMBQ/Boredoms)

Guitar / synth player Shinji Masuko started a relief fund and as of March 16 has collected $2200. Donations can be made through Paypal at dmbq[at]dmbq.net Read Masuko's explanations after the jump

iTunes

American customers can donate to the American Red Cross through iTunes.