As you are probably well aware, along with the release of Windows 7 RC came some big news that affect Visual Basic 6.0 applications: Professional and Ultimate Editions of Windows 7 will feature a Windows XP Mode for backwards compatibility with legacy applications. This means that even if you are using components that have issues with Windows 7, you will be able to run your VB6.0 application on the new operating system, albeit within a Windows XP virtual machine.

It is important to mention that the VB team over at Microsoft was already making sure the IDE and VB6 runtime would work on Windows 7, as I commented before (second comment on that post) based on the Support Statement for Visual Basic 6.0 on Windows Vista, Windows Server 2008 and Windows 7:

The Visual Basic team is committed to “It Just Works” compatibility for Visual Basic 6.0 applications on Windows Vista, Windows Server 2008 and Windows 7.
The Visual Basic team’s goal is that Visual Basic 6.0 applications that run on Windows XP will also run on Windows Vista, Windows Server 2008 and Windows 7. The Visual Basic team is also committed to the Visual Basic 6.0 development environment running on Windows Vista, Windows Server 2008 and Windows 7.

The objective of XP Mode is clearly to move forward the Windows architecture to the latest technologies, free of all the legacy bits required to maintain compatibility of old applications (read the History posts at the The Old New Thing blog for examples), while at the same time it allows developers to smoothly upgrade their applications without the threat of the application not working in the new OS. It is basically a compromise of old vs. new. And it is very easy to draw parallels between XP Mode and the approach taken by Apple, first with Classic and then with Rosetta, to smooth the transition to new platforms. But as was the case in those scenarios, Classic was eventually phased out, and Rosetta will eventually be as well.

I personally think that this technology may end up being around for a while, and may even end up included in the next versions of Windows if there is enough customer demand for it. This has to be the same technology used in their Microsoft Enterprise Desktop Virtualization (MED-V) solution, targeted towards enterprise customers:

“Microsoft Enterprise Desktop Virtualization (MED-V) provides deployment and management of virtual Windows desktops to enable key enterprise scenarios. MED-V 1.0 helps enterprises upgrade to the latest version of Windows even when some applications are not yet compatible.”

Even in the scenario that XP Mode is supported for a long time, you still have to consider it as something that can be used for a smooth transition while you upgrade your applications to the .NET Framework, and not as an excuse for not upgrading. It can help you plan a gradual migration, were you first start migrating certain modules while leaving others in VB6, with tools like the Interop Forms Toolkit. And keep in mind that even though the application will run, the IDE is simply not supported anymore and neither are most controls that cause compatibility issues. And at the same time you will be missing the benefits of using the latest technologies and the increased productivity of the .NET Framework.