Wikiquote.org is an offshoot of the popular online interactive encyclopaedia wikipedia. It is a database of thousands of quotes by notable figures from both the past and present.
From the opening page, you have the option to select from any one of the many languages that wikiquote is available in. These languages range from the most commonly spoken to the obscure. The more obscure languages have fewer listings than the popular ones. From the bottom of the page you can follow the link to any other wikipedia-based website, including wikitionary, wikinews, wikibooks and more.
The default option for the search menu is English, though other languages can be selected from the pull-down menu. Quotes in the database are sorted by the person who spoke them, so typing a quote into the search function is not necessarily a reliable way of finding its speaker. Quotes by notable people are divided into sections based on where, when or in what media presentation they said it. Within the file on a notable person, you can quickly select a particular source by clicking within the table of contents.
As with all Wikimedia initiatives, each page can be edited by anyone who has registered with the site. These edits are reviewed and moderated to prevent vandalism. Each page also has an area for discussion, often about proposed edits. There is also a history so you can see what changes have been made to the page.