The Wii Speak Channel can be used again, thanks to combined efforts with RiiConnect24 and Wiimmfi. If you have a Wii Speak, you can register Wii Friends with RiiConnect24 and chat over Wiimmfi. You can also send voice messages to other users via Wii Mail, even if they don't have a Wii Speak.
Clicking the blue button above will take you to the download page of auto-wiiware-patcher. The Windows version of the tool has an option to download and patch the Wii Speak Channel.
If you don't have a Wii Speak, Amazon sells them for a low price.