Today you learned how easy it is to access components created in other languages using managed C++, both in managed and unmanaged C++ applications. You also learned how you can easily access components created using managed C++ by other CLR languages such as VB.NET and C#. As other languages become available on the CLR platform, accessing components created using these other languages should be similarly simple.
You've accomplished a lot over the past 21 days. You spent the first week learning the basics of building Windows applications using Visual C++. You built on that knowledge during Week 2 by learning about more Windows programming topics that built on the knowledge you learned in the first week. Finally, in the Week 3, you built on all that you had learned in the first two weeks by diving into some advanced Windows programming topics. You finished off the third week by learning about some brand new topics that have been introduced with Microsoft's new .NET platform. At this point, you've got a good general knowledge of building applications with Visual C++. From here you might want to pick out some specific topics that you want to explore in more depth and pick up a more advanced book that focuses on those particular topics. Good luck!