(If the hotlink fails, the link to the image is here.)
The ones I already know are:
Aries - Yuno Gasai from Mirai Nikki - Future Diary
Taurus - Shion Sonozaki from Higurashi no Naku Koro ni
Gemini - Misa Amane from Death Note
Cancer - ?
Leo - ?
Virgo - ?
Libra - Rena Ryuugu from Higurashi no Naku Koro ni
Scorpio - ?
Sagitarius - ?
Capricorn - I *think* this is Rika Furude from Higurashi no Naku Koro ni
Aquarius - Katsura Kotonoha from School Days
Pisces - Kaede Fuyou from Shuffle!