Omniglot is a guide to the writing systems and languages of the world. It also contains tips on learning languages, language-related articles, quite a large collection of useful phrases in many languages, multilingual texts, a multilingual book store and an ever-growing collection of links to language-related resources.
You can find a guide to the contents of Omniglot on the sitemap, and a list of all the writing systems and languages featured on the site in the A-Z index.