I'm studying for my first LPI certification (first computer certification at all), and found this
http://www.grymoire.com/Unix/Sh.html .
Very succinct and clear. I suggest also getting a bash pocket reference to make comparisons with the Bash shell which has a few extra things to know and to read part of the Bash manpage about initial files, but this tutorial is the best thing I've seen for Bourne or Bash. It covers everything you need to grok the Bourne shell, fast.
