Hindi Dictionary (Hindi Sabd Kosh)
Although you'll be better off getting hold of a printed version of English to Hindi and Hindi to English Dictionary, some online versions of Hindi dictionary do exist.
Online Hindi Dictionary
Some Links to Online Hindi dictionaries
http://www.shabdkosh.com
http://dsal.uchicago.edu/dictionaries/platts/
http://www.infobankofindia.com/newdic/englishtohindi/GetHindi.htm
Check out one available at
http://www.aksharamala.com/
Hindi Dictionary at the above site is also available as Google toolbar
button which makes it convenient and easy to use. Use the URL below to
set it up in Google toolbar of your browser. (Note: you must have Google
toolbar already available in your browser setting)
http://toolbar.google.com/buttons/add?url=http://www.aksharamala.com/e2h.xml
Unicode Hindi Dictionary
La Trobe University, Australia has prepared an unicode version of Hindi dictionary. This basic Hindi dictionary contains the vocabulary introduced in the lessons and exercises in their Hindi language study programme. It contains around around 900 words. The explanations of terms given are just working definitions and are not intended to substitute for more complete grammatical explanations, or working through the materials.
An updated unicode version of this Hindi Dictionary is now available (December 16, 2005) click here to access it.
Hindi Dictionary Software
Hindi dictionary Software resources are under review and will be featured shortly. Meanwhile you can look in Products section for it.