wxWindows is an open source GUI framework to make cross-platform programming. wxWindows gives a single, easy-to-use API for writing GUI applications on multiple platforms. Link with the appropriate library for your platform (Windows/Unix/Mac, others coming shortly) and compiler (almost any popular C++ compiler), and the application will adopt the look and feel appropriate to that platform. wxBasic is a free, cross platform Basic interpreter that can generate stand-alone GUI executables for Windows and Linux. It combines the simplicity of Basic with the portability of the cross-platform wxWindows library.
May 2006. New version: many bugs corrected and some new features added.
September 2009. A new version of wxBasic is available now. The new version is linked against the wxWidget 2.8.10 library and support the most important classes. New wxAuiToolbar classes is integrated. Is was compiled with gcc and do not depend on any external runtimes or libraries. Now we started a MacOSX Version. You can use the dmg image and drag & drop wxBasic into your Program folder. Thanks Andreas.
As explained by Slayer below, last versions of wxBasic are not developed by the original authors.