Apple is all set to unveil the new iPhone OS 4.0 today. The company sent out invitations last week to press for the promised a “sneak peek” at where the company is headed with the iPhone’s native operating system.

Among those features being thrown onto Apple lover’s wish lists are third-party app multitasking, aggregated e-mail, personalization options, turn-by-turn navigation, cloud-based music service (Lala) and expanded Bluetooth support. Whether iPhone users will get all that or more is unknown, as the ever secretive Apple is famous for bringing out big surprises at its media events.

A spring preview event is quickly becoming an Apple ritual. In March of 2008, Apple took the wraps off its iPhone SDK, and just last March, the company unveiled the iPhone OS 3.0. Actual launch of the software has run concurrent with Apple’s June or July release of new iPhone models.