Esperanto

L. L. Zamenhof created Esperanto based on some amazing dreams about global understanding and ease of communication. Here is a nice quote from him:

Ĉian ofendadon de homo pro tio, ke li apartenas al alia gento, lingvo, religio aŭ socia klaso mi rigardas kiel barbarecon.
I consider as barbaric any offence to a human being because he belongs to a different people, language, religion or social class.
- Ludoviko Zamenhof

The language is a constructed language with standardized and easy grammar. The words are derived from European languages as well as ancient Latin and Greek. Many related words can be built from every stem using different grammatical endings, suffixes, or prefixes. If you know English, French, and/or Italian you are almost half way with learning the language.

The best way to start learning is to use Kurso de Esperanto which has 12 nicely devised lessons.

Here are a list of great websites to get more information:
1) How To Learn Esperanto
2) Lernu!
3) esprento.net
4) Esperanto portal and literature
5) Esperanto-USA
6) Basic courses to learn Esperanto
7) Esperanto
8) Books in Esperanto: project Gutenberg

Glossary/phrases/dictionary:
1) Esperanto-English Glossary
2) Useful Esperanto Phrases

In Esperanto:
1) Ĝangalo
2) Esperanto Radio Arkivo
3) Wikipedia in Esperanto

In French:
1) Gerda malaperis
2) Cours Gratuit d'Espéranto