This is the English American series of the popular Japanese Series Card Captor Sakura.
Sakura Avalon a 10th grader, one day accidentially opens a magic book, found in her basement. When opened the 'clow cards' that were contianed within the book excaped, to reep havock on the earth.
It is now up to Sakura to recapture the cards as she is now a Cardcaptor.