I just got a T-shirt from Zebrahead, the punk/rap outfit from CA. They have 2 tsunami relief t-shrits which are pretty rad, and it acts as a donation (plus shipping).
Here's the link:
http://zebrahead.bigcartel.com/product/zebrahead-loves-japan-relief-fund-shirtiTunes also have the "Songs for Japan" album (although the track listing is questionable, all money goes towards the Red Cross)
Feeder released a single "Side by Side", and again all money is donated. You can also donate on their website:
http://www.feederweb.com/Thanks for the other links, I'll be donating for the Red Cross too.
I had an idea for a drama-drive (Writers stay up all night writing a play, rehersals and stage prep happens in the day, performance in the evening) but I have so much other work on right now its kind of hard to fit it in and get interest for it.
But I'll post back when I have some more links. I think its cool that so many bands and organisations have gotten involved.