Lots of books are out there. These are the ones I've found that I like.
For beginners I highly reccomend Teen Witch by Silver RavenWolf. Its the book I got when I first stepped into Wicca, and it is by far in my opinion, the best book I have found for newbies to Wicca. Silver's hompage is here, and you can order it from there.
The follow up to Teen Witch is To Ride a Silver Broomstick, which is also by Silver RavenWolf. I havn't read it yet, but I think Silver is a good enough writer to say that this book will be good.
Superstitions by Peter Lorie is quite a good book, though it does not involve witchcraft.
Now, at this point in time, these are all the books I know of that are really worth while. There are more, I'm sure, and as I read more, I'll get more posted up.
You can always got to Ebay or Barnes and Noble.com to find more books.