Yeah, get the "Standing In The Shadows of Motown" book/CD set. Also by Dr. Licks is the book ("Funkmasters"?) about the James Brown bands. That's a great learning tool because he goes into details of bass, drums, and guitars and how they work together.
For first lines, I wouldn't tackle "I Want You Back" or "Bernadette". I'd start with "You Can't Hurry Love" as MysticMicheal suggests. And of course "My Girl" as long as you learn the bass line, not the guitar lick- well, OK learn the guitar lick so you can teach it to your guitarist, but know it's a guitar riff, not bass... And "This Old Heart of Mine", "Ain't Too Proud to Beg", and then maybe move up to Gladys Knight's version of "I Heard It Through The Grapevine" (MUCH better record than the more popular Marvin Gaye version, and I love Marvin!).
Have fun, and once you think you've got the song nailed, work it up playing it only with your index finger of your plucking hand. Extra points for tackling "Bernadette" and "What's Goin' On" with heavy flats (55-110) and a seriously bowed neck...
jte