Apple Computer Inc. will release a version of its wildly popular iPod digital music player next month aimed at the unwashed masses who rely on Microsoft Corp.’s Windows computers, ending months of anticipation from hopeful enthusiasts.

But it brings with it a classic dilemma for the penny-pinching audiophile: Most PC users eager to make the switch will need to get a special add-in card for their computer to link to the new Windows-based iPod MP3 player, boosting the cost of an already pricey system.