Can I program EV3 with the NXT-G IDE?
No, it appears that you need to use the EV3 software to program the EV3 kit, as per the FAQ on the LEGO site: http://mindstorms.lego.com/en-us/News/ReadMore/Default.aspx?id=476781

The EV3 sensors also won't work with the NXT brick either.

Though, I'd imagine if you're getting an EV3 kit, it should come with the EV3 software.