An object-oriented programming language developed by Microsoft that can be used in .NET.
Visual Studio 6 (for the VB6 IDE) isn't free. If you have a paid subscription you can download it, otherwise try Ebay.
A better alternative is to download the free twinBASIC programming IDE which is VB6 compatible and can compile to 32-bit or 64-bit. There is a free community edition of twinBASIC.