According to the cover note of the Tankobon volume 3, a manga "Nyankoi!" was announced to get an anime adaptation. It has been published in an online manga magazine "FlexComix Blood
" since 2007.
Kousaka Junpei is a high school boy, who is suffering from an allergy to cats. One day, he accidentally destroys a guardian deity of cats (Neko Jizou
) and receives a curse. He has to accumulate good deeds to one hundred cats in order to break the curse. Otherwise, he'll be turned into a cat.
Source: Scan of the cover