If you have iTunes for Windows and have iOS apps saved on your Windows computer, you cannot actually use the apps in any way on the computer. The one exception would be if you jailbreak, you can be able to use anything on your iPhone's display on your computer. I am not sure how that works, but I know it is possible.
Yes but not as Many as an iPod or iPhone
no because the apps are for an apple iphone and apple wants you to buy a mac so that they can make more money
There is a lot of discussion if the Windows phone is a good replacement for the iPhone. They have a lot of the same capabilities and available apps. The Windows phone has live tiles which is an improvement on the iPhone.
Of course it is okay to play with your phone, they even have Apps for that
you cannot play iPhone apps on your computer. And if you want to open games from your iTunes then you cannot either. iTunes is only for songs or games, videos, photos and apps for iPhone.
No. Some apps have been ported to OSX and you can download them from the new Mac App Store (comes preloaded on all new macs, comes as a part of Snow Leopard.) But you can't play straight iphone apps.
You buy the iPhone app
apple create the apps on iPhone
Not if the app says that it's not iPod touch compatible. Some apps can work on iPad, iPhone, and iPod touch, but some will only be for one or the other.
no you cannot use ipod and iphone apps on itunes, but you can buy the apps on itunes and put them on your ipod and iphone
Although iPads can download apps made only for iPhone/iPod Touch, the iPhone can only download iPhone or iPhone/iPad apps. Apps made only for the iPad do not appear on the App Store. Luckily most of these apps have an iPhone counterpart such as Angry Birds (iPhone) and Angry Birds HD (iPad only).
You cannot play the Facebook games and apps on your Nokia Lumia 520 windows phone since you did not download the right app.