Nyan koi! manga

Nyankoi! summary:

The story is about a second-year high school student named Junpei Kousaka, who not only hates cats but also is allergic to them. Unforunately, he happens to have a crush on a girl, Kaede Mizuno, who really loves cats. On the way home from school one day, Junpei kicks an empty can and happens to accidentally hit the Guardian Deity of Cats. Now he's able to understand cats but was practically given a curse. He has to grant 100 wishes in total from any cat or he'll turn into a cat himself. Note: After March 2010 this series went on hiatus in Japan.