Here is a link to a free 10 lesson correspondence course in Esperanto.
From the introduction:
"Esperanto is a living language, used for everything people use any other language for. But it's much easier to learn than a national language. Even people who can't remember a word of a language they studied for years in high school or college need only months of intensive study to become fluent in Esperanto. It is also more useful than national languages if your goal in learning a language is to get to know people from different places, since virtually everyone who speaks Esperanto has learned it for this reason."