I received a phone call from Nintendo informing me that I had been approved as a developer about a week before Christmas and that they would send me an email with a link and login to order the devkit. I haven't received this yet. Does anybody know if this is normal or has something gone wrong?

Their support staff is very responsive and friendly, my guess is your email with all the good stuff was stuck in a spam filter moments after the phone call.

If you already created an account at warioworld attempt to log in there where you may be pleasantly surprised. If that doesn't work for you, email support and ask them to resend your information.