Can I sync my Windows Mail contacts into iCloud?
I don't use Outlook for Windows, only Windows Mail.
I'm Michael and I work for connex.io and we do just that.
connex.io is an app that can sync, de-duplicate, clean and up-date your Address Book automatically. This means that you can sync between different devices such as your iPhone and Windows Live mail easily. Not only that you can sync it with a lot more devices and services (such as Facebook for example). You only have to connect them once and everything will be done for you automatically.
No, it's not possible.
Instead of syncing to iCloud, you can add your Windows Live Account as an email account, and choose "yes" for syncing contacts and calendars. This will sync your iPad and iPhone with the information saved on your Live Account. But that will only work if you have that on your account, not in the Windows Mail application.