Digital Painting 101: The Complete Guide
One thing I have to tell you guys who are interested in this (not my thing; I'm so bad at drawing, *stick figures* laugh at me—but I can write pretty well) is to try getting yourself a tablet laptop (NOT an iPad or Android slate) with a WACOM Penabled screen. My fiancee is a professional illustrator, classically trained, and she's so enamored of her now 3 year old Gateway C-140x laptop that I don't think she'll ever give it up as a drawing tool. Particularly if you're on a budget, you can get these laptops pretty cheap on ebay (she paid a lot more when they first came out, but today they can be found for about $350-400) and they're upgradeable to pretty recent Core 2 Duo processors if you need more heft. They run photoshop just fine in their stock configuration. Anyway, the reason why is because these laptops have a stylus, and the screen can detect up to 256 levels of pressure sensitivity. Not quite as awesome as a Cintiq, to be sure, but a lot cheaper especially for a student.
Related: Concept art
Related: Tutorials (photo & drawing mostly)