We are slowly but surely getting more answers about Wii Speak. Nintendo confused a lot of us with the original press release, and since then, they've let us know that we can indeed buy a used Wii Speak mic and still get a download ticket for the Channel. Now they step in with Edge to give everyone more details.

EDGE: I have purchased a third-party microphone which is said to be compatible for the Wii. It does not come with a Wii Speak Channel code, can I still get the service?

Nintendo: No, when Wii Speak is bought (Either as a bundle or standalone) you get a Wii Download Ticket for the Wii Speak Channel to download the channel, this is the only way to obtain the channel.

See the answers to three more questions here