dont know much about it personally, but from what ive read, the remote controller is needed and you only have to spend a fiver to get wii play, which by all accounts is stupid, but is a game for 5 pounds.
I bought an extra controller with Wii pplay and it is definately worth the extra £5.
There are several mini games on there and they are designed to introduce players to all the functions of the controller but are fun as well especially with 2 players.
As it seems to be the only way to get an extra controller at the moment I'd say it's worth it. The games are a bit of a mixed bag, simple but fun and as said above, primarily show off how clever the controller is. They are aimed at 2 player mode although you can play with 1 player. I ended up buying three to get the controllers (poor planning that ), and have put the spare copies of the game on ebay.