A great manga, you guys!!! It's probably a must read among manga fans especially ladies. :P *g*
Anyway, about this series: Fruits Basket to have 22 volumes. Currently, the japanese version goes up to 20 (Vol. 21 scheduled for release September 19, 2006). The english USA volume goes up to 14, and the english Singapore/Australia goes up to 19. (Yay!!!! I'm off to buy volume 17 + 18 + 19 when I get back to Singapore and try to find some time to actually read some manga!)
Here below lies some things to get to understand this great manga! :-) (Beware that below might include a slight bit of Spoiling, not exactly...)
This manga, Fruits Basket, follows the life of the high school student, Tohru Honda, recently orphaned when her mother is killed in a car crash. Tohru lives with her grandfather, but when his family moves in, and remodelling is performed on the house, Tohru resorts to living in a tent, unwilling to impose on her friends, and holds down a job to support herself. Despite suffering many hardships, Tohru remains her cheerful and optimistic self.
One day, Tohru comes upon a house in the woods which is the home of Shigure Sohma and Yuki Sohma (an admired and worshipped, yet aloof, boy from her school) from the Sohma family. When the Sohmas discover that Tohru is, in fact, living in a tent in the woods, they are quite surprised. The entire area is Sohma property, and Tohru pleads to stay, offering to pay a rental fee for living on their land. Feeling sorry for her, and desperate to end their take-out eating habits and filthy living conditions, the Sohmas offer her their spare room in exchange for cooking and housework. When her tent is buried that night in a landslide, she has no option but to accept.
Tohru soon discovers the Sohma family's secret, and the reason why Yuki is so private and taciturn; thirteen members of the family are possessed by the 12 animal spirits of the Chinese Zodiac ("Jyūnishi" in Japanese) and the spirit of the cat. They transform into animals when hugged by the opposite gender, or when they are under great amounts of stress. When she promises to keep their secret, the Sohmas allow Tohru to keep her memories rather than hypnotically erasing them, a fate that has previously befallen everyone who had found out.
The story follows the lives of Tohru and the Sohma family, as they deal with each other and a society where neither quite fits in, as well as the feared Akito Sohma, head of the Sohma family.
I guess you can say this is one of the cream of the crop in Shōjo Manga being the best sellilng for Shōjo Manga in 2004 in the US! The drawings are great, nice crisp and clean! The only one thing I don't like is the first two books' framing that's a bit hard to read. But besides that, Fruits Basket is absolutely scrumptious! BTW, if you haven't already guessed it, there's an Anime out already with 26 episodes...However, the anime series only closely follows the manga up to approximately the end of volume 8 of the collection.

Yuki Sohma
Source: http://en.wikipedia.org/wiki/Fruits_Basket