Apple's newest version of its Macintosh operating system will be set loose on Friday, hitting the market after a four-month delay due to the company's work on the iPhone.

Leopard features include playful "iChat" video-conferencing and a "Time Machine" that resurrects lost data.

Time Machine automatically copies music, pictures, applications, files and "absolutely everything" a person puts on their Macintosh, according to Apple vice president of platform experience Scott Forstall.

The operating system enables people to remotely search for files on all computers connected to their network.

Leopard also has simple tools for people to create "widget" applications that stream feeds such as news or syndicated cartoons from websites onto small windows on computer screens.

It includes improved text-reading, Braille support, and closed-captioning for people with disabilities.

Modifications to iChat allow people linked via web cameras to share slide show presentations, playfully distort their pictures or insert fake backdrops.

Leopard marks the sixth version of OS X.