Wall Street Journal, which gave a rather gloomy forecast for the PS3 earlier this week, has an extensive preview.
According to the book, Sony, Toshiba and IBM started working on the Cell in 2001 and planned to spend $400 million over five years. If everything went according to plan, the PlayStation 3 would be out by Christmas 2005. In 2002, Microsoft approached IBM about making a chip for what would later be known as the Xbox 360. IBM ended up making a new chip "built around the core" of the Cell it was currently creating for Sony. In the end, Xbox made the 2005 launch (with a time bomb under the hood) and Sony came out a year later.
As the WSJ points out, for all the power and money behind Microsoft and Sony's consoles, Nintendo has outsold both using a "sound strategic vision" with the less-powerful Wii.