Dogboy:

Have a look at this for starters: http://en.wikipedia.org/wiki/Old_English

The most famous text in Old English (aka Anglo-Saxon) is probably Beowulf. There is a recent bilingual translation by Seamus Heany that you can probably find at any Barnes and Noble or Borders (probably in poetry or classics). It's a good read, but the Old English part is only barely recognizable as English. (Don't read it aloud in public unless you want someone to think you are one of those Lord of the Rings nerds.)

Middle English (few hundred years later) is a lot easier (although still a challenge). The obvious example there is Chaucer's Cantebury Tales (make sure you aren't reading the modernized version that probably give kids in school).

Fun story -- a friend of mine was interviewing for a job (she's a lawyer) and she had on her resume that she had studied Anglo Saxon at Oxford. The lawyer interviewing her totally floored her by speaking to her in Anglo Saxon (this was at a NYC firm). I've heard of people testing out claimed language skills, but that was something she was not expecting.