Paso a Paso website http://www.pasoapaso.com
Grammar exercises http://www.colby.edu/~bknelson/SLC/index.php
vocabulary & grammar resources http://www.spanishpronto.com/spanishpronto/
Holt, Rinehart and Winston http://go.hrw.com/
National Spanish Exam, practice exercises and tests from past years http://www.nationalspanishexam.org
Listening practice - Spanish Audio Gazette http://lab.chass.utoronto.ca/rescentre/spanish/index.html
Hoy - Spanish language newspaper and video clips http://www.vivelohoy.com/
Dictionaries http://www.wordreference.com