Infoworld has some rumors about Microsoft being interested in porting Silverlight to the iPhone. They suggest that it will be hard for them to achieve this:

Microsoft is reportedly¬†very interested in pushing Silverlight on Apple’s devices. But it’s well known that Apple ultimately controls what software runs on the iPhone — so good luck, Microsoft.

I think Silverlight will be appearing on the iPhone sooner than many people think. Microsoft is pushing this hard, and they are already working with Apple when it comes to other software (Office for Mac, RDP client, MSN, et cetera). As long as MS can prove that it won’t be consuming too much CPU and that it’s stable enough not to crash Safari, there are no downsides for Apple. And if they play it well, they might even get paid for including it. After all, Flash is coming Real Soon Now as well, right?¬†