Here's a tutorial on machine by Kevin Knight.  This is gives excellent, accessible coverage and we'll go through this in class to get a grasp of how MT works.

Knight1999StatMt_wkbk.rtf

Here are some other references that cover specific techniques or comparisons.   

BrownDelaPietra1993_J93-2003.pdf

AlignCompare-J03-1002.pdf

HMMWordAlign-p836-vogel.pdf