training manuals
Use to have an Esprit training manual at one company I worked at -- can't remember which company's manual it was -- and it was ok for learning basics. You could have tossed the 3D milling portion of it out the window though, as machining anything that way would have gotten you tossed out of a shop. I guess I could say that for most manuals though... especially when it comes to their "advanced" sections.
If that's what you're interested in, you might want to get a good feel for the content before plunking down the cash.
The Manufacturing Reliquary
http://cmailco.wordpress.com/