eBay has released details on the most popular auctions from the beginning of the Christmas season, including (you guessed it) figures for the PS3 and Wii.
For the period of November 17th through November 24th, the Playstation 3 sold in 14,675 individual auctions. Including both the 20Gb and 60Gb PS3s, the average winning bid was $1186 (about 215% of retail).
For the period of November 19th through November 24th (since the Wii launched on the 19th), the Wii sold in 26,708 individual auctions. The average winning bid was $412 (about 165% of retail).
Note that the Wii sold at a smaller margin, though at a significantly higher volume within a shorter time period. The Xbox 360, for comparison, sold in 331 individual auctions within approximately these same dates. Since November 24th, the average winning bids for all three consoles have been falling, but are expected to spike again near Christmas.
Source: Gamespot.com