Quizlet (vocabulary--there is an app. Create an account and sign up for the Spanish II class for the app to be data free.)
Vistas (vocabulary, grammar, reading, writing, listening, tutorials, etc.)
Twitter (assignments)
Linguee (translate in context--there is also an app. Download the ES-EN dictionary for offline use)
Fun learning Spanish: Cool site with (interactive) crosswords and space invaders (scroll down to find other options)
Spanish 411 (lessons by topic)
Study Spanish (search by topic for additional help)
Advanced Practice (search by topic for additional help)
Conjuguemos (grammar practice by topic)
Lyrics Training (sing/type song lyrics in Spanish)
Word reference (translation)
About Spanish (more practice by topic)