That may be when they'll announce the price to the public, but it's quite clear that retailers have been given some information from Microsoft regarding the price. GameStop, Amazon, Best Buy, and Wal-mart all have it listed as $149.99:
http://www.gamestop.com/Catalog/ProductDetails.aspx?sku=020055&loc=ntlalone
http://www.amazon.com/Kinect-Xbox-360/dp/B002BSA298/ref=sr_tr_1?ie=UTF8&s=videogames&qid=1276779650&sr=8-1
http://www.bestbuy.com/site/Microsoft - Kinect for Xbox 360/1036858.p?id=1218212157998&skuId=1036858&st=kinect&cp=1&lp=1
http://www.walmart.com/ip/Project-Natal-Xbox-360-Xbox-360/13378144
And these figures match up perfectly with the pricing given to Edge and MCV by industry sources last month (including $299 Arcade bundle):
http://gamrconnect.vgchartz.com/thread.php?id=110169&page=1
