Valentine (2001)

Genre: Horror | Thriller
Tagline: Love Hurts.
Starring: Denise Richards, David Boreanaz, Marley Shelton, Jessica Capshaw and Katherine Heigl.

Plot: Four Friends start to receive morbid valentine day cards. Someone out there is stalking them....someone they all spurned when they were younger. And Valentines Day 2001 is the Day she/he gets their revenge.

http://www.imdb.com/title/tt0242998/
http://en.wikipedia.org/wiki/Valentine_(film)