No prob, Fawn, as an artist I'm always happy to help other artists however I can.
1. Yeah, Painter is probably the best program for digital painting there is, in my opinion, since it lets you emulate natural mediums and get a lot of personality in your strokes. It's miles ahead of Sai, which is great thought, it takes up very little from your computer and it's good for more anime-ish style painting, quick, clean and simplified, but it's not the best for realistic painting.
2. I tend to use grisaille for most paintings, yeah, it's an amazing method and it lets me change hues at will while keeping all my values intact, saving me a TON of time. That way I don't have to use local colour, either. For bigger paintings I tend to separate each plane in a layer and overlay the hues on them independently. Then I add some general color overlays over everything so the lighting matches in all parts of the image. For other images, however, more cartoony, anime-ish stuff, I use local color.
3. Inspirations, tons, Wayne Barlowe, Keith Thompson, Tsutomu Nihei, Sergio Toppi, Range Murata. Honestly I haven't really used many books and the sort for digital painting. I learned acrylic and gouache painting and transplanted some stuff from that onto hte computer. Learning the traditional approach will usually make you much better at the digital stuff, so the best advice I can give is.. learn the traditional approach >,>. In any case, Gnomon video tutorials can help.
Also, here's a small face tutorial I did a while back and thought it'd be good to have on here. As usual, click to enlarge.