I believe the OP is asking about a cross-compilation environment, such that you can develop code for the iOS under a MS-Windows-based development environment. Personally, I know nothing about doing this, but I just wanted to clarify.
Yes, I'm doing as you mentioned. I said some articles on the net and also do procedures that will make it possible to code xCode even if I'm in Windows. It is said that I need to download VMware in able to do that, and to install MAC inside the VMware. Although I got an error while i try powering up the machine (MAC). I also learned that Virtualization is not enabled in my PC (I'm using Probook 4430s) by running some tests. That's why now I'm trying to enable it.
I also got another choice. Instead of xCode, It is also likely possible to develop apps using android in some SDK like MoSync (thanks to caperjack) or Eclipse.
What I really like to do is to develop Apps for iPad and iPhones. :)
So I think, I'll just do whichever may be possible.