A few years back Jeff Scovil published a book about mineral photography. While it is "pre-digital camera", there is much very good information in it about lighting, framing shots, various ways to construct your studio, etc. I would highly recommend it.
If you are planning on going digital rather than film, I highly recommend getting a good digital SLR camera with the capacity for changing lenses. These are more expensive than the pocket-type cameras, but they are much more versatile and you will get much better photos. I use a Canon EOS 400D, I know others who use Nikon. Both are good cameras. You will also need to get good photo editing software. Adobe Photoshop is the industry standard, but is quite expensive and time-consuming to learn. You may want to start with a more basic program such as L-View Pro or PaintShop Pro. Both of these will perform all the basic and necessary functions for you.
If you want to take photos using a microscope, this is a whole different game. You will also need to invest in a good stereo microscope (trinocular is best for taking photos) and a fiber optic lighting system. There are some very good photographers using microscopes who post here on Mindat, and I know there have been many discussion threads specific to doing this.
