VB6のIDEのサポートは既に終了していますが、Windows 8 にもランタイムは搭載されます。
As detailed in this document, the core Visual Basic 6.0 runtime will be supported for the full lifetime of Windows Vista, Windows Server 2008, Windows 7, and Windows 8, which is five years of mainstream support followed by five years of extended support.
Support Statement for Visual Basic 6.0 on Windows Vista and Windows Server 2008