Verb Conjugator http://users.ipfw.edu/jehle/VERBLIST.HTM This link is a great reference if you need to check the conjugation of a verb. The list of verbs is quite comprehensive and if you can't find the verb you're looking for, see if you can find a similar one or one with a similar root.
Spanish Listening Practice http://www.laits.utexas.edu/spe/siteindex.php This site from the University of Texas, Austin is great for practicing listening comprehension. There are different levels from beginning to advanced and there are videos as well.
Extensive Spanish culture and language http://cvc.cervantes.es/portada.htm An amazing website for learning everything there is to know about Spain. There is also an excellent section called "Aula de lengua" for Spanish language lessons (check out "Pasatiempos de Rayuela").