They said it'd be here on launch day, and they were right!
http://www.nintendoworldreport.com/news/32525
A system update has been released for Wii U on the evening before launch day.
The system update should include many of the touted features for Wii U, including the ability to play Wii games on the console, and transfer games and save files from Wii.
This update does not include Nintendo TVii, which will be included in a system update in December.