Your English is fine GoodOrange.
Any apps you download on any device are linked to the Windows Live ID on the phone.
If you have another Windows Live ID, you can't transfer any apps over I'm afraid.
You could always set up a windows live ID for yourself and purchase MetroTube in Zune.
I think you can purchase the apps in Zune without having a phone.
Then it would be available for your phone when you get it.
Welcome along to WPCental GoodOrange. :)