Language Details: F#

F# is a strongly-typed, functional-first programming language for writing simple code to solve complex problems.

Official website (see also: Wikipedia article)
Code Jam 2009 Contestants using F#
Qualification Round
Used in 18 solutions by 3 contestants:
Round 1A
Used in 4 solutions by 2 contestants:
Round 1B
Used in 4 solutions by 2 contestants:
Round 2
Used in 2 solutions by 1 contestants:

Submission Origin

Australia (1 contestant)
Kyrgyzstan (1 contestant)
Netherlands (1 contestant)
Russia (1 contestant)