Since the 2005 version, Microsoft has offered free editions of its Visual Studio IDE. First it was Express editions, which are still available, and recently there is the Community Edition too. Express targets a specific language or technology and has some limitations, including lack of support for extensions, while CE is basically Professional but free for developers in particular scenarios. Neither place restrictions on what an individual developer can do with the work they produce.
It's hard to remember everything significant that has come along since 2003 but I'd say that the three things that stand out most to me are data access improvements, including improvements to typed DataSets and the introduction of the Entity Framework, improved multi-threading support in the Tasks Parallel Library and the introduction of LINQ. There's also the MVC Framework for ASP.NET apps, meaning that we no longer have to suffer with Web Forms, WPF for Windows apps with far greater support for many things than Windows Forms and WCF for web services and other communications functions.
Most of the code that you would have written back then will still work but there are now better ways to do various things. I'd probably suggest checking out MSDN and the What's New pages for the various versions of VB and VS over the years and then research more deeply those topics that sound of interest.