The Windows-Installer for Groovy 1.5.1 can now be downloaded from the Groovy Website (direct link). It takes care of the gory details of a Windows installation, copying files, setting environment variables and file associations.
The installer contains the Groovy 1.5.1 Binaries, API Docs and a PDF snapshot of the Wiki, the native launcher, Gant 1.0.2, Scriptom 1.5, version 0.4.2 of GraphicsBuilder, SwingXBuilder 0.1.5 and JideBuilder 1.0. The installation of everything but the binaries is optional.
Currently supported languages for the installer are english, german, spanish, french and brazilian portuguese.