If you like this stuff, I really, really recommend The Thrilling Adventures of Lovelace and Babbage. It's a great half-comic-book half-historical scholarship. The second half is contained in footnotes and primary sources, which are about half the book, and it's delightfully fun.
Dover Books printed an edition containing bits of Passages from the Live of a Philosopher and with Lovelace's translation and amplification of Menabrea's paper on the Analytic Engine: http://store.doverpublications.com/0486246914.html . I don't know what happened to my copy. You can get his On the Economy of Machinery and Manufactures at Gutenberg, http://www.gutenberg.org/ebooks/4238
fun story - cto of my old job had a mug with a picture of babage on it that he was given as a gift or an award or something.
he was very proud of it, so naturally we (tech team) stole it, hid it for a month or two, created the same image that was on the mug in photoshop and ordered a replica online.
We then created a fake email account and started sending him ransom emails ending with a video of the replica mug getting smashed. good times.
