Well... first, you're going to need a Mac. You're going to have a tough time developing on a Windows machine of any kind.
You'll then need to acquire a developer's license from Apple and the SDK for iPhone
and iPad (which only runs on a Mac, so again, you Windows machine is useless). You'll also need to learn objective C, because there are no "app-builders" out there for people who don't actually know how to program.
If you only have access to Windows, I suggest you try developing for Android instead. You can do that on Window or a Mac.