For the sake of those who don't quite understand zby's comment all the way, I'd like to point out that Unicode is a character set where as UTF-8 is a character encoding. A character encoding is used to encode the characters from a character set into bits and bytes. A character set is an abstract thing, so converting from an encoding to a character set doesn't make a whole lot of sense (unless you are going to then encode the characters into another encoding). Moreover, UTF-8 already uses the Unicode character set.

Your question should properly be, "how do I encode a UTF-8 file as UCS-2LE." UCS-2LE is just another encoding, it is not Unicode.