Apple has shown off some of the 100 new features to be included in the iPhone operating system later this year.

The update includes a mobile advertising platform called iAd that will be used to place adverts in applications made by third parties.

Apple founder Steve Jobs also showcased a long-awaited multi-tasking feature, which will allow users run more than one program at a time.

The feature is already included in many other smartphones.

iAd marks Apple's first foray into a potentially lucrative new market, and pits it directly against Google's search engine advertising model.

Apple will allow external developers to pocket 60% of ad revenue from iAd.

The Apple boss said the iPhone OS 4.0 update will be released first for the iPhone and iPod touch, and then the iPad, later this year.