I haven't cooked to much with seaweed, or had a lot of experience eating it, I've used agar-agar a fair bit in place of traditional gelatin in some dessert recipes - it works great.
I like the Japanese style of thinly slicing strips of seaweed or using seaweed flakes sprinkled over top or rice, noodles, soup, etc. It gives a subtle, natrual green and yet pleasantly salty taste to whatever it's added to.
There are some neat recipes including one for seaweed bread, and a salad which largely resembles Waldorf salad made with Irish moss on this page:
This site also has recipes, as well as some info on different types of seaweed:
(Vanwingen. I just have to say again that I apologize for accidentally deleting your other post today.)