Google Translate has now included Hindi in its list of languages. So now you can translate 'English to Hindi' or 'Hindi to English'. See also few useful tools available with Google Translate. You can read English sites in Hindi or Make your own site avalable in Hindi or English. The translated text for Hindi would be in Devnagri.
But don't start celebrating yet! Translated text does not follow the grammar or syntax of Hindi. For example "My name is Sukhdev Singh" would be translated as "मेरा नाम है सुखदेव सिंह", when it should be "मेरा नाम सुखदेव सिंह है". You can suggest Google the right translation by clicking on "Suggest a better translation". It may improve translation quality in future by learning from suggestions.