I think this board is the best place to try to find the answer.
I once bought ikura (in jar) from a japanese classmate before. That japanese lady told me she ordered it online(from U.S.) and the flavor was so great .
Later I lost contact with that japanese lady and I tried to buy ikura from some online stores and thought they should be the same. I was totally wrong.
The one that I got is un-seasoned and it's really bothersome that we have to use mirin and soy sauce to add the flavor every time. (and it always tasted not that right).
I know that there are some nice japanese supermarkets in some cities that sell fresh ikura. Unfortunately that we don't have one here. So I really like to know where to find a good online store to buy the japanese-style seasoned ikura.