ReadFluent
ReadFluent is a bilingual e-book reader for iPhone, iPhone Duo, and iPad.
Read the original. Understand the translation.
Import an EPUB you already own and read it in the language it was written in. When you want the meaning of a page, ReadFluent translates that page with the system translation on your device. On a wide landscape window, such as an iPad or an open iPhone Duo, the original and the translation sit on facing pages. On a phone, you switch between the original page and the translated page.
You can pick the language you are reading toward. A bookmark saves the passage, not a screen position, and opens that place again later.
The page can be warm white, paper sepia, or charcoal. That choice stays on the device.
ReadFluent is the app I wanted while reading a book in a language I was still learning: the original stays in front of me, and the translation is there when I need it.