CIA now accepts email FOIA requests.

The CIA has begun accepting Freedom of Information Act requests via email.

The forms are located way inside the CIA website (www.cia.gov), inside the Library, Freedom of Information Act Electronic Reading Room, and then third entry down (marked by dots) under the title. https://www.cia.gov/index.html

"What is electronic reading room?"

There is then a link to take you to the procedure format: FOIA requests can now be made online.
http://www.foia.cia.gov/foia_request/start

However the CIA will only respond to FOIA requests using snailmail.