I want to develop an iOS mobile app using Xamarin in Windows. Can Apple Mac OS run on a virtual machine in Windows, rather than run on a separate physical machine as build host?
If possible, any link to the setup would be appreciated, for running Virtualbox, Windows 7, Mac OS.
http://developer.xamarin.com/guides/ios/getting_started/installation/windows/
As stated above, it is not in Apple's terms of agreement to run OSX on anything but an Apple product so you shouldn't do it.
Although if for some educational reason you were to install OS X Yosemite ("Hackintosh" ) inside of Virtual Box on Windows, set the Network adapter to "Bridged Adapter" and get the Xamarin build host installed and running (as well as Xcode from the App Store), then it might be possible to connect from Visual Studios. But as stated, you shouldn't do it ;)