Windows-PowerShell-Indent-File is a project mainly written in Vim Script, it's free.
Simple indenting rules for Windows PowerShell
This is a mirror of http://www.vim.org/scripts/script.php?script_id=1815
Sets up a customized version of cindent for use with PowerShell. Best used with the Windows PowerShell syntax and ftplugin files (vimscript #1327 and vimscript #1816)