-Go into iTunes
-Plug your ipod in
-Find the audiobook in the iPod section (The iPod tab. Idk if audiobooks are considered music)
-Right click on the audiobook and press properties (might be a similar word)
-Find the tabs at the top of the screen, and click the one on the farthest right (Think it's called "other" or something)
-There should be an option in there to tell in to remember where you left off.