Best way to convert text files between character sets?

Question

What is the fastest, easiest tool or method to convert text files between character sets?

Specifically, I need to convert from UTF-8 to ISO-8859-15 and vice versa.

Answer 1

Assuming, you don't know the input encoding and still wish to automate most of the conversion, I concluded this one liner from summing up previous answers.

iconv -f $(chardetect input.text | awk '{print $2}') -t utf-8 -o output.text