I am going to start building iphone applications , but i don't have Mac, can i do that on windows? can I use the virtual machine?
not that i'm aware of though there is MonoTouch but again i think that runs on a mac.
you can create a Mac virtual pc using vmware and the steps are online if you google mac vm i think.
google "mac vm on windows"
at least then you won't need to buy a mac
Buy a second-hand Mac Mini or similar from a reputable online auction site and you're there.
All you need then is Xcode which you can get from the Mac App Store (MacOSX 10.7+ for Xcode 4.1 or assuming you've subscribed to an Apple Developer program you can find older versions for older Macs)