Information on Nintendo's game counseling hotline says so.
Nintendo of America's game counseling hotline, the Nintendo Power Line (425-885-7529), also features news on upcoming games and systems. If you listen to the current version of their news section, you can select an option to hear about the next-generation Revolution console. It features an introduction that contains a very interesting piece of information. Here's a word-for-word transcript:
"As the company with the strongest heritage of innovation, Nintendo moves the bar for all next-gen systems by employing a wide-ranging strategy that will attract more kinds of gamers to more kinds of games. When Nintendo's
new console, codenamed Revolution, arrives in the later half of 2006, everyone will discover the meaning of all-access gaming."
We've seen a "Spring 2006" date, and more recently a vague "2006", but this is the first confirmation from Nintendo itself that Revolution will ship in the second half of 2006. We'll have to wait and see if this turns out to be true.
Thanks to Patrick Ross at NintendoNow for the tip!