It's there... just tucked away where Ninty apparently doesn't want you to find it. Here's where it is:
1). Instead of going to Wii Channels, go to Settings and Features
2). Click on Wii Download Ticket
3). Enter your Wii Speak code
4). You'll be prompted to download the actual Wii Speak Channel. Just do it now, 'cause if you wait 'til later, you'll have to enter the code all over again. It's 65 blocks, IIRC. So make sure you have the space before you go through all this!
5). Go back to the main Wii menu and select the Wii Speak Channel
6). You'll have to do some basic set-up; just follow the prompts.
There you go!
I'm fiddling around with it now. Is anyone else interested in testing it out!?