WizTools.org Text Encoding Util
Text Encoding Util is a command line tool to convert text files from one encoding to another, and to test if a particular text file is compatible with the charsets defined in particular encoding.
The binary is published as executable Jar. The usage:
$ java -jar text-encoding-util-NN.jar help
This tool is available as part of "The Joy of Unix in Windows Tool Bundle":
Java 5 or above.