Apple on Thursday announced plans to preview the latest version of its iPhone software, OS 3.0, on March 17th. The company plans to hold one of its trademark special events Tuesday at its headquarters in Cupertino, Calif., to show off "an advance preview of what we're building" for the iPhone 3.0 software release, according to an invitation distributed Thursday.

Being used to the company’s style of approaching its new releases, the fact that the invitation doesn't give any hints about what features the new software will have doesn’t come as a surprise whatsoever; but clearly indicates that we'll get a look at them. "Get an advance preview of what we're building," reads the invitation. 

Apple's new software emerges as the global economic crisis has hit the market for iPhones and other smartphones. The market researcher IDC Corp. on Thursday lowered its 2009 worldwide smart phone sales growth forecast to 3.4% from 8.7%.

Next Tuesday's 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. While a hardware update is intriguing, there are many software-related features iPhone users have been anxious for since its debut.

Gene Munster of Piper Jaffray thinks Apple may finally demonstrate a "universal search capability" as part of the new software. There's no real way to search your iPhone on the device's home screen, although individual applications such as Contacts have their own search functions, of course.

Apple last updated the iPhone softwarein November 2008, when it pushed the operating system to Version 2.2 as it patched a dozen security vulnerabilities and added several new features, including Google Street Views, to the smartphone's mapping application.