Apple, which has earned praise for its easy-to-use online music store, said the new iPod, which has a 40-gigabyte capacity, costs $ 499 and is now available.

Cupertino, California-based Apple also sells a 10-gigabyte model for $ 299 and a 20-gigabyte model for $ 399. They can all be used with both Apple Macintosh and Windows computers.

Apple, whose music store is integrated into its popular iTunes music jukebox software, will offer a version of the music store that works on Windows computers later this year.

The music store lets customers sample 30 seconds of any song for free. Each song costs 99 cents to purchase. Customers can buy and download single tracks or entire albums.

Apple also announced on Monday faster versions of its iMac desktop computers, which have either 15- or 17-inch flat panel displays that float above the computer's lamp-base-shaped central processing unit.

The faster iMacs have PowerPC G4 microprocessors running at speeds of up to 1.25 gigahertz, or running at 1.25 billion cycles per second, and boast faster memory and graphics chips.

The new iMacs also have the faster USB 2.0 connection for linking devices such as digital cameras and iPods to the computer.