This provides only a part of the epic, but if you want to see the original text (transliterated in Roman characters) side by side with an English translation, then this is the book for you! Be sure to use the Hathi Trust or Google Books presentation so you can see the facing text pages with the translation lined up; the Gutenberg edition separates the English text in a way that makes it harder to see how the original and translation match up.
The book is available at Project Gutenberg, Hathi Trust, and Google Books. You can get a free Kindle ebook from Amazon too!
This post at Open Culture provides an audio recording of an Akkadian version of the epic: Hear The Epic of Gilgamesh Read in Akkadian.
