Good overview of subjunctive and if clauses. More than you ever wanted to know...
Verbos de obligacion y deseo
http://conjuguemos.com/home/docs/php/list.php?type=verbs&division=verbs&language=spanish
http://www.colby.edu/~bknelson/SLC/
http://www.studyspanish.com/tutorial.htm
http://www.trinity.edu/mstroud/grammar/
http://www.spaleon.com/sub_pres.php
Muchos ejercicios de repaso http://www.auladiez.com/spanish/spanish_exercises.html