Apple will hold an event next Tuesday to preview new software for the iPhone OS 3.0, the company said on Thursday.

The invitation sent out to select media doesn't give any clues of what the new operating system will feature, but Apple says that this will be an advance preview of what we're building.

Apple will also give information about the new software kit that third-party vendors use to create applications for the device.

The event will be at its corporate campus in Cupertino, California, on March 17.

The preview comes about a year after iPhone OS 2.0 came out. Many of the recent rumors circulating about a new iPhone have focused on a hardware update rather than a software update.

The 3G iPhone proved to be an immediate hit with consumers and the company sold 6.9 million devices in the September quarter and 4.3 million in the December quarter.

In 2008, Apple sold over 13.7 million iPhones, ahead of its 10 million target.

By January, Apple said more than 500 million applications had been downloaded and that more than 15,000 apps were available.

Shares of Apple rose $2.91, or 3.14 percent, to $95.59 in afternoon trading on the Nasdaq.