There is no longer any advantage to taking pictures on film. For an introduction to digital photography see these articles by Charles Maurer. Start with the first or the third. Although they appear in a Macintosh newsletter, little of their content is specific to Macintoshes. Virtually all of the software described works under Windows as well.
Reality & Digital Pictures
An introduction to photographic representation. Most people should read this article first.
The article also compares three outdated versions of Photoshop, but this comparison can be ignored. Modern editing tools are described below in "Digital Ain't Film".
Colour & Computers (and FAQ)
Most people find it difficult to control and balance colour. This article explains why—the problem is not you—and it describes a simple approach that ought to be adequate for most purposes.
Sense & Sensors in Digital Photography (also errata and FAQ)
An introduction to the technology of digital cameras that is based on basic principles of optics and visual perception. This article explains how image sensors work then distinguishes between (1) how many pixels are needed on a sensor to capture information and (2) how many additional pixels must be interpolated in a print to present that information to the eye. This article also compares Bayer vs. Foveon sensors. Be sure to read the errata as well.
How Not to Buy a Digital Camera
Camera reviews are less informative than they appear to be. This article explains their problems and a more sensible approach to buying cameras than poring over reviews.
A Feast for the Fridge: Printing Digital Pictures
How to choose and use a photo printer. This article also disscusses the interaction of size and content, and compares poster-sized blow-ups from a Foveon sensor and film. Details of the models available are out of date but the principles have not changed.
Cataloging Photos & Storing Them on the Computer
The problems of keywording & reviews of Aperture, Expression Media & Extensis Portfolio.
Digital Ain't Film: Modern Photo Editing
How to edit photographs a modern way, by making vector-based changes instead of painting bits.