Madhur Jaffrey's World Vegetarian is great.http://www.amazon.com/Madhur-Jaffreys-World-Vegetarian-Meatless/dp/0609809237/ref=pd_sim_14_1?ie=UTF8&refRID=0QNEACZSNDMVF0ZS03YE&dpID=51A6ptm%252BXNL&dpSrc=sims&preST=_AC_UL160_SR138%2C160_
Not exclusively Indian but it sounds like that's not your biggest priority.
I manage the kitchens at a large meditation retreat center that serves only vegetarian food and we serve quite a few Indian meals so I can give you a few basic tips:
1. Buy whole seeds for spices: cumin, fennel, coriander, brown mustard, cardamom pods, fenugreek etc. You'll be tempted to buy them by the pound if your excited about getting into it but onjly buy what you will use fast. Almost every Indian meal starts with toasting whole seeds in a cast iron skillet then grinding with a mortar and pestle or electric grinder. It only takes a minute of hands on work and your house will smell fantastic.
2. Make ghee. Its easy, it stores indefinitely, and its indispensable AFAIK
3. Learn to make Indian breads: Naan, chapati etc. Even if you don't bake they are super easy and some, like chapatti, can be mixed up and cooked on the spot, no need to rise for hours. A baking stone or large cast iron skillet is helpful.
4. Paneer is super easy to make and super expensive to buy, so make it if you like it.
5. Get a little rice cooker. You can measure some basmati, rinse, measure water and turn it on at the beginning and now you have a component of the meal being cooked for you not taking up a burner.