Ah, clever Rowling. Giving us a small fix of her world, to spread the Harry Potter Magic a little bit further (as if it still had further to go).
This is really just a book of "fairy" tales a la the Magical World. Apparently, if we'd been raised as wizards and witches, we would've heard these tales at our mother's knee. Which, to be honest, is a little scary, in same cases - since at least one is pretty seriously disturbing. Although, when you think about our own fairy tales, they're pretty disturbing too, I guess. Beedle's got the witch who turns herself into a "stump," a crabby son of a wizard with a crazy pot, a journey to a magical fountain as well as the infamous tale of the three brothers that we learn about in the 7th book.
The tales themselves are fine. Witty, in some cases, maybe a bit slow in others. My 9 year old daughter, that I read this one aloud to, enjoyed them all. What I found the most entertaining, however, was the "commentary" by Albus Dumbledore that follows each story. He puts the tales in "historical context" and often references people/circumstances that hard-core Potter fans will relish recognizing.
If you loved the series, it's worth reading just to spend a little time with Dumbledore again.