The Apple iPhone SDK hasn't had any leaks so we haven't seen anything and don't know what to expect. Apple released their software roadmap, and the even is scheduled for 6th March, and it is confirmed in a email sent out by the company, that the SDK will (finally) be announced then.

I'm seriously wondering what these enterprise applications are, perhaps we can expect a full office package, containing applications that will make your computer feel useless. Besides this faith that we have in the office package, crucial business compatibility with Exchange and Outlook should be added to make the iPhone usable by major corporates.

Source: Engadget, AppleInsider