Novell has recently provided a kit to enable iPhone application development using .NET based languages. Leveraging the Novell Mono runtime the kit will enable iPhone applications to be developed in for example C#.
This is potentially huge because Objective-C, the default language used for developing iPhone applications is relatively unpopular among developers and .NET based languages are much more productive to work with. .NET based languages are also very popular with line of business applications so this opens the path for software companies with a wealth of .NET experience to leverage this experience and start expanding there applications on to the iPhone.
I personal currently have a Windows mobile phone primarily because I know I can easily develop software to run on the phone and I can use my phone as a suitable test bed for applications we are developing for clients. I have always found my phone a bit clunky and if I am honest suffer from a bit of phone envy when sat next to someone with a much slicker iPhone. With the opportunity to easily develop applications on the iPhone I think I will be purchasing one shortly to assess what is possible.