The Nintendo 3DS will be getting a slightly beefier hardware revision. The oft-supposed second circle-pad add-on will be a no show in this edition, though.
The Nintendo 3DS XL adds a rounded form factor, 90% larger screens, and a slightly higher price. The top 3D screen comes in a 4.88 inches while the bottom, touchscreen clocks at 4.18 inches. That's inching (sorry) closer to the 5" screen on the PlayStation Vita, but not quite.
The 3DS XL battery will also get bumped to 3.5-6.5 hours while playing games (compared to 3-5 on the 3DS proper) and 6-10 hours while playing DS games (compared to 5-8). That doesn't mean the 3DS XL (or LL as it's dubbed in Japan) will come with an AC adapter.
Charging comes separately, so if you plan on upgrading, be prepared to hold onto your AC adapters. Three colors have been announced: White, Red/Black, and Silver/Black. The revision will be available in Japan on July 28th (just in time for New Super Mario Bros 2) for 18,900 yen. The 3DS XL will be available in America on August 19th for $199.99 in Black, Black and Blue, and Black and Red.
[UPDATE] Here are some officially released shots of the box and hardware: