VBA (Microsoft Visual Basic for Applications) is still available in AutoCAD 2013 but it is not included with the installation media. Find the VBA for AutoCAD downloads here at http://www.autodesk.com/vba-download. There downloads are found also for AutoCAD 2010, AutoCAD 2011, AutoCAD 2012 in both 32-bit and 64-bit.
If you have existing VBA this can be good news but don’t get started to develop anything new in VBA for AutoCAD as we don’t know if this will be the last release with VBA or not. Consider to convert the code to .NET (C# or VB.NET) and if you like help with it please feel free to contact us.