CUPERTINO, Calif. » Apple says the smaller version of its new, slimmed-down iMac desktop computers will go on sale Friday. It will also start taking orders for the larger model, but the units won’t ship until next month.

The model with the 21.5-inch screen will cost $1,299 and up, depending on the configuration. The model with a 27-inch screen will start at $1,799.

The iMac tacks the computer components to the back of a large LCD screen. The new models have no disk drive, helping make the edges one-fifth the thickness of the old model. They bulge considerably toward the middle of the back, however.

Apple revealed the new models a month ago.

Apple shares fell $2.04 to $587.49 in afternoon trading.