Watch the On My Trail online guitar lesson by Jeff McErlain from Blues Guitar Fakebook: Rhythm Vol. 2
Here's the Robert Johnson classic "Hellhound on My Trail". This one is really tricky I must say, as the form is rather odd, so if you decide to play it with a band, you must work it out ahead of time. Of course, listen to the original, I also highly suggest the version I'm drawing from by Eric Clapton.