EPUBReader is a Firefox addon which lets you read ePub-files just in the browser. You don't need to install additional software!
If you click on a link to an ePub-file, you are normally prompted by the Firefox "save as" dialog. With EPUBReader installed, the ePub-file is downloaded, processed and directly displayed ready to read.
It runs on every operating system Firefox does (Windows, MacOS X, Linux).
EPUBReader is available in 23 different languages: Catalan, Danish, Dutch, English, Esperanto, Finnish, French, German, Greek, Hebrew, Hungarian, Italian, Japanese, Lithuanian, Polish, Portuguese (Brazilian), Portuguese (European), Russian, Simplified Chinese, Spanish, Swedish, Traditional Chinese, Turkish.