So far she has appeared in four movies, if you count her upcoming one. She appeared in Kim Kardashian: Superstar in 2003, an adult movie which did a lot to launch her celebrity career.
In 2008 she appeared in Disaster Movie, a comedy directed by Jason Friedberg and Aaron Seltzer. The film was a failure with both critics and audiences, and Kim Kardashian was nominated for a Golden Raspberry award for her poor acting (along with five others in the same film).
In 2009 she was in Deep in the Valley, another adult-themed movie in which she played a girl called Summa Eve.
Her latest film, named Temptations: Confessions of a Marriage Counseler, is directed by Tyler Perry and will be released in March 2013. Tyler Perry is a very high profile American director and actor, and the new movie is considered to be quite a big career move for Kim Kardshian.
Besides film work, she has of course appeared in many TV shows and documentaries, most famously in her family's reality show Keeping up with the Kardashians.