Using Hindi interface for Vista
I was an avid user of the Hindi Interface for Windows XP. When Vista was released, this Hindi interface was not available. Now it has been released and is available for download:
And if you are looking for language interfaces in other languages than Hindi, refer: http://www.microsoft.com/industry/publicsector/government/locallanguage/default.aspx
you can find Bengali, Gujarati, Kannada, Konkani, Malayalam, Marathi, Punjabi, Tamil, Telugu there amongst others.
All one needs to do is download and install the package. After installation, the system will ask you to logout and then log back in. this should get you the language interface you installed.
in my case, after the logoff/ login, I had to go to control panel and change the display interface from "Language and Interface Options".