Breathalyzer_BKTree is a project mainly written in C, it's free.
facebook puzzle breathalyzer using Levenshtein distance and BK Trees.
To compile and build the executable:
gcc -o breathalyzer breathalyzer_BKTree.c
To execute:
./breathalyzer input_filename
input_filename should contain input which adheres to the specification given here. http://www.facebook.com/careers/puzzles.php?puzzle_id=17
This prints a closest matching word for each input word and it also prints the total edit distance/cost. This can be changed to print all closest matching words for a given input word, if needed.