Apple announced the immediate availability of new iMacs on Tuesday with 21.5-inch and 27-inch LED backlit displays. The new iMacs ship with Apple's wireless keyboard and new Magic Mouse, foregoing the USB-based keyboards and mice that have shipped with every iMac to date.

The new iMacs sport Core 2 Duo processors starting at 3.06GHz, or Core i5 and i7 quad-core processors, 4GB RAM with support for up to 16GB, an 8x SuperDrive, Gigabit Ethernet, a FireWire 800 port, four USB 2.0 ports, an SD card slot, Mini DisplayPort for video out, built-in AirPort Extreme and Bluetooth, an iSight camera, and built-in speakers and microphone. The new iMac body also includes edge-to-edge glass on the front and an all aluminum body.

Apple's new 25.1 and 27-inch iMacs

Apple seems to have movies in mind with the new iMac, too. It's built-in display offers a 16:9 aspect ratio, and both sizes sport at least HD resolution at 1920x1080 for the 21.5-inch model, and 2560x1440 for the 27-inch model. Apple also claims the built-in speakers offer clearer and louder sound with better bass response.

The displays use IPS display technology, too, which offers a 178 degree viewing angle without color distortion.

The 27-inch model can be used as a display for other home theater devices, too, thanks to its ability to accept input from external DisplayPort sources. Extra cables and adapters will be required, but they aren't yet available.

The 21.5-inch 3.06GHz model includes a 500GB 7200RPM SATA hard drive, and NVIDIA GeFores 9400M integrated graphics for US$1,199. It's also available with a 1TB 7200RPM SATA hard drive, and ATI's Radeon HD 4670 graphics card with 256MB RAM for $1,499.

The 27-inch 3.06GHz iMac ships with a 1TB 7200RPM SATA hard drive, and an ATI Radeon HD 4670 graphics card with 256MB RAM for $1,699. It is also available with an Intel Core i5 2.66GHz quad-core processor for $1,999.

Intel's quad-core 2.8GHz Core i7 processor is available as a build-to-order option for the 27-inch iMac, too.

The 27-inch display in the new iMac is now the largest LED backlit display Apple offers on any of its products, leaving only the 30-inch Cinema Display using the older CCFL backlight technology.

The 21.5-inch and 27-inch Core 2 Duo iMac models are available now, and the Intel Core i5 and i7 models will be available in November.

[This article has been updated with additional details about the new iMac's features.]