I found it online (amazon). It is actually seaweed. You can make jello type desserts with it. I have used it to make raspberry pies also.
Warning though, it is not super creamy and I think I would try using 1/2 teasp. agar agar powder because it was a little too firm. (still good though)
You also might like more sweetner, I don't like things real sweet.
You can use flakes or powder, the flakes you had to let them soak in the liquid for a half hour or so and then cook it. The powder you can just cook. I think you would have to use a little more of the flakes also. The powder turns out to be a lot cheaper than the flakes too.