Hi there Pepper,
As for English websites, here are a few to start looking for an apartment in Paris:
http://www.my-apartment-in-paris.com/ www.parisattitude.com/ www.paristay.com/
As per my understanding, these sites cater to non-French speaking people assuming that most of them are coming to Paris for holiday or short or long term stay for leisure and propose mostly chic areas at exorbitant prices.
Since you are moving to Paris, I assume that you already have a staying arrangement/ hotel for a few weeks till you zero in on a place to live in. While you are here, check out various rental agencies in your hotel's neighbourhood (Century 21 etc.) Paris has lots of rental, estate agents! Almost all of them have printed booklets available at their entrance, just pick a few up from different agencies to get an idea of the kind of places that you like and their prices. That should help you narrow down your choices instead of going through a distance-sales as in through some website.
However, if you are still interested, with some basic French, you could manage to widen your choices with:
www.seloger.com www.avendrealouer.fr www.paruvendu.fr www.lodgis.com/fr/ www.pap.fr www.appartement-a-louer-paris.com
As far as transportation is concerned, as long as you are in Paris, there is absoltely no issue with metro stations accessible at close distances (hardly 5 or max 10 min walk). In addition, there are buses, trams, sub-urban trains and even bicycles on rent

14th, 15th, 16th are good neighbourhoods. Mostly, its best to visit any neighbourhood without having any pre-conceived ideas and you will yourself get the feel as to its attractiveness or not. A generalization may inflate your expectations (and from estate agents' view, budget too

)
Ex-pats are scattered and you can't find any particular area with a concentration of ex-pats or even Indians (except in sub-urban Boulogne with Indian embassy crowd or Bobigny with Punjabis). However, no matter where you are, if you are friendly (and your neighbours' too), mixing around won't be a problem though with my experience, I find that being self sufficient in the beginning and later widening the circle with various mutual interest groups is most beneficial.
Prices vary according to the location. It could be from 1200-2000 Euros.
All the best !