Nintendo Company Ltd Fall Summit 2010 just announced the official release date and price for the 3DS in Japan. February 26th 2011 and it will cost 25000 yen (about US$299). Confirmed launch colors are Aqua Blue and Cosmo Black.
It will have a "virtual console" for GB and GBA games (all of them displayed in 3D!) and take SD cards up to 32gb.
US release in March 2011.
It will feature a "Passive Tag Mode" that downloads info from other 3DS consoles as you pass by them, and WiFi connection on Sleep Mode that downloads updates and other software when it's on standby. Home button gives way to some multitasking, like playing your own music in the background while you play games.
No word on region locking (though it's pretty safe to assume it will be there) or the official US price.
Will update as more details and videos leak.
Nintendo 3DS Software Lineup Movie
Subject: Nintendo 3DS Update (Release dates, price and new features!) 
Wed Sep 29, 2010 8:33 pm