Watch the Single Note Rhythm online guitar lesson by TrueFire from Play Country Guitar 2: Rhythm & Lead Fundamental
Playing a great song like the "Folsom Prison Blues" is a fun way to work on single note rhythms. Picking through this song will make you keep your timing of your single note playing in the pocket. If your timing gets off, the whole song and feel suffers, so do this slowly and make sure you get the coordination between your fretting hand and your picking hand down. That is what will keep you in sync.