The Register reports that the Revolution will hit the 2006 holiday season:

"As for North America, we need to release it by Thanksgiving, or otherwise we won't receive support from the retail industry. So the Revolution will be released prior to that period."

More importantly, they recognize that there's an important price barrier:

Iwata wouldn't be drawn on the console's price, but he did claim it will be "affordable".

"The amount of money that people are willing to spend on video games is getting less every year," he said. "Even if it's a superb machine, it's not going to sell if it's ¥50,000 (£246/$433). We plan to make [Revolution] an affordable price."

I think he's right about the price - Nintendo has managed to hit the impulse buying range with the GameCube - under $100. The Revolution will be higher than that, but it sounds like they know that there's an upper end to the impulse range.