The software, named Boot Camp, works on all Apple Macintosh computers that use Intel processors. It is free public beta release that will be incorporated into the next version of its OS X operating system, Leopard, expected this summer.

Apple shares rose by 9% on the Nasdaq exchange after the annoucement.

Demand

Phil Schiller, head of worldwide product marketing for Apple, said he thought there would be demand for the patch.

He said: "Ever since we introduced Macs using Intel chips, we've had some customers asking, 'Hey, can you run Windows on these Macs as well?'"

Boot Camp will allow users to run both Windows XP and Apple's Mac OS X operating software.

The release of the software, which is available as a download from the Apple website, was also welcomed by Microsoft.

By allowing its computers to run Windows XP, Apple could attract people who want Macs - considered by many easier to use and more stylish - but who are used to running Windows.

Apple, which celebrated its 30th birthday on April 1, will move its entire Macintosh line to Intel chips by the end of next year.

Apple introduces Boot Camp, press release