Some iPod owners have complained that new-generation iPods display inaccurate battery charging data, so Apple has posted a brief technical note to help.

"The iPod battery indicator shows, approximately, how much charge is left in the battery," Apple explains. It discusses situations in which the indicator will show there is charge left in the unit, but is in fact out of power.

Apple also explains that: "The iPod battery indicator may show less than a full charge after fully charging the iPod for four hours. This does not necessarily mean anything is wrong with your iPod's battery."

It suggests users import an album of average-length songs at 160kbps, place the album on a fully-charged iPod, and leave the album playing on repeat setting until battery power expires.

"iPod (with Dock Connector) should play the album for approximately eight hours, while the (older) iPod should play the album for approximately ten hours", the company says.

Apple in the US has introduced an iPod AppleCare Protection Plan for both Mac and Windows users. This $59 plan extends service and support coverage and its accessories for up to two years. It offers telephone and Web-based support, repair and servicing, and is available for all iPods within their one-year warranty.