I'm maintaining that Wii Fit will have a ~30% attach ratio, so that around 18 -20 million by early 09, but I think Ps3 will sell around 24 Million by that time, so....close but no cigar. It won't outsell it till 2010.
*disclaimer - If WiiFit gets bundled with Wii for a discounted price expect it to outsell the Ps3 by/before chrismas 2009.
Playing : PC AOE, DiRT 2, Runes of Magic, Wings of Prey & Planetside 2
Wii U : Nintendoland, Super Mario U & Fifa 2013 demo
DS : Guitar Hero : On Tour
Formerly unknown as Vengi