Apple said the new models have up to 12 hours of rechargeable battery life, compared to about 8 hours with the current crop. The prices are $299 for a 20-gigabyte model and $399 for a 40-gigabyte model--each $100 less than their earlier counterparts.
Since Apple introduced the first iPod in October 2001, the market for large-capacity, hard drive-based music players has grown increasingly competitive, with rivals such as Dell Inc. and Creative Labs trying to undercut Apple in price.
Competitors also boasted better battery life--the Dell DJ has about 20 hours while the Samsung YP-910GS lasts about 10 hours. The upcoming Creative Zen Touch promises 24 hours of battery life while the new Sony Network Walkman, due to be released in August, promises up to 30 hours of continuous playback.
Despite the challengers, Apple has sold more than 3.7 million iPods and leads with about a 60 percent share of the hard-disk drive player segment in the United States and about a 30 percent share of all portable music players, according to The Yankee Group market research firm.
"Now we're turning the heat up even more, and we're continuing to push the edge in the technology," said Greg Joswiak, Apple's vice president of hardware product marketing.
The new iPod versions are also thinner and have improved software features, including a quicker way to shuffle songs and a variable playback speed of audio books, Apple said.