Unlike the old models, the new 3DS and 3DS XL have NFC-tech built in, meaning they can communicate with Amiibo figurines (like the ones coming for Super Smash Bros.) without need of an extra device. Nintendo's also introduced a Micro SD slot underneath the base cover, while new "Super Stable 3D" functionality is designed to ensure the 3D features stay sharp and comfortable, even when the 3DS is rotated (see below).
The new devices also have revised dimensions, as shown in images below. Furthermore, the 3DS cartridge slot has been moved to the front, leaving more space on the back for extra buttons. The handheld's back now features R, ZR, L and ZL buttons, with the power adapter slot moved center. Meanwhile, the battery life of the new 3DS is 3.5 to 6 hours when using 3DS software. For the 3DS XL, it's 3.5 to 7 hours. Nintendo also notes the new 3DS screens are larger than those of the old model.
The new models launch in Japan on October 11, with the new 3DS priced 16,000 yen (around $154) and the new 3DS XL 18,800 yen ($181). The new 3DS XL will be available in Metallic Blue and Metallic Black, and the new 3DS in White and Black. A Nintendo press release notes: "As for the overseas markets, our local subsidiaries will separately confirm. However, there will be no U.S. and European launches this calendar year."
Update: Nintendo unveiled Wii JRPG Xenoblade Chronicles for the new 3DS. The company says the game will only run on the new 3DS, and that's because of its enhanced CPU. Also, check out some of the covers you'll be able to customize the new handheld with.