Fantastic website for beginner to intermediate Spanish students! Endless interactive games that are very easy to use. Completely free to create an account and join.
Very extensive site with complete explanations to commonly challenging Spanish grammar such as Ser vs. Estar, stem changing verbs, use of the preterite, etc,. Your answer for every Spanish problem! Applicable for all levels of Spanish.
Free to sign up and use, hundreds of lessons and categories in six different levels (Beginner to Advanced). You can even have a native speaker correct your homework! Does cost money though.
(Real Academia Española)
Complete dictionary to help with grammar and spelling. For students with a high level of Spanish (site is completely in Spanish). Endless verb conjugations!
This web site is a great tool for those students who need help with verb conjugations, looking for if a word is masculine or feminine, would like to compare translations, hear the pronunciation, looking for synonyms, definitions, or need to know the idiomatic meaning of an expression.