Here's a list of sites that I've found incredibly useful or inspiring throughout my work with Tarot:
• 78 Notes To Self
• Aeclectic Tarot: Tarot Cards, Reviews, Readings, eBooks & Info
• The Alchemical Egg
• Alchemy Website: The Artwork of Modern Tarot
• Association for Tarot Studies
• Black Fire on White Fire
• Card Games: Tarot Games
• The Elegant Tarot Project
• Mary K. Greer's Tarot Blog
• MetaFilter's posts about Tarot
• The Silicon Dawn Tarot
• Taroteca
• The Victoria Regina Tarot
Here are some resources related to other forms of divination and insight:
• The Abysmal
• Ask MetaFilter
• Astroinquiry
• BibliOdyssey
• Do You Think I'm Smart? Astrology and Other Ass Munchery
• Black Phoenix Alchemy Lab
• The Hermitary
• The Illuminates of Thanateros
These are the decks that I prefer to keep on hand for readings:
• Alchemical Tarot
• Hermetic Tarot
• Secret Tarot
• Tarot of Marseilles
• Thoth Tarot
• Victoria Regina Tarot
• The Visconti Tarot
• Waite-Smith Tarot
Tons of books have been written about Tarot-- some good, but many almost depressingly awful. The shelves at your local bookstore are glutted with "introductory" books that all completely contradict each other. This is probably inevitable (due to reasons I've outlined here), but finding the right book can make a big difference in how far you'll go.
The best book that I've read about Tarot to date is Robert M. Place's The Tarot: History, Symbolism, and Divination. Place has made several stunning decks, but I believe his enduring legacy will be this book, which is an incredible beginner's guide in its own right, but more importantly is also a historical study of the Tarot and how it became what it is today.
Here are a few more that I've found helpful. You'll notice these aren't at all limited to instructional texts; my lists cover a wide spectrum of styles and interests that creatively intersect with themes from the Tarot. Beware, I recommend different books for different reasons, so if you have additional questions about something on this list, please feel free to ask me personally. As usual, your mileage may vary.