I am not Hindu, but I have some passing familiarity with the religion and culture from my interfaith work. I've researched in that direction for some of my writing.

Some vocabulary:
http://familybible.org/teaching/religions/VocHinduism.htm
http://uwacadweb.uwyo.edu/religionet/er/hinduism/HGLOSSRY.HTM
http://www.translation-services-usa.com/hindi_vocabulary.php

For names, a good online source specializing in Hindu names is:
http://www.indianhindunames.com/
Lots of extra articles and resources support the main name lists.

For culture, this site contains many articles plus the text of entire books online:
http://www.hindunet.org/
Here's one that breaks down into concepts, practice, lifestyle, and traditions:
http://hinduism.iskcon.com/

I was also fascinated by this map of the languages of India. Wow, I wish there were a website that would do this for the whole world!
http://www.mapsofindia.com/culture/indian-languages.html