I'll Take You There by The Staple Singers contains one of the coolest ever bass lines as well a tasty little solo. It's quite easy to play too so you should definitely learn this one!
David Hood was bass player for the Muscle Shoals session group who laid down this track in 1972. There's a great documentary about the group you should check out.
Drum Beat Play Along
I'll Take You There is 100BPM so set your metronome there or download the drum backing.
Soul Bass Patterns
Soul and RnB music is dominated by a few patterns that are easy to learn and hear. Check out the full lesson here and the patterns below. Make sure you train your ear to hear the sound of the pattern.