Apple Computer Inc. (AAPL) on Tuesday posted a quarterly profit that quadrupled as the company sold more than 6.5 million iPods (search), the digital music player that has rejuvenated the maker of Macintosh computers.

Apple said net income for its fiscal fourth quarter rose to $430 million, or 50 cents per share, from $106 million, or 13 cents per share, a year ago. Revenue rose 56 percent to $3.68 billion.

Analysts had expected a net profit of 36 cents per share, on average, on revenue of $3.74 billion, according to Reuters Estimates. In July, the company forecast fourth-quarter revenue of about $3.5 billion and earnings per share of about 32 cents.

Apple has about a 75 percent share of the entire digital music player market, according to market research firm NPD Group. Last month, it unveiled its pencil-thin iPod nano (search), which replaced the iPod mini, then the best-selling iPod version.

Shares of Apple trade at about 30 times estimated net earnings per share for its fiscal 2006 ending in September and shares of No. 1 PC maker Dell Inc. (DELL), which is focused on volume sales, trade at about 17 times its estimated net earnings per share for its fiscal 2007 ending in January of that year.