Language Learning Programs: DU's library offers a list of language learning resources that are open to current students, including popular online courses, such as Livemocha.
WordReference.com: A good online dictionary
Grammar
StudySpanish.com: Designed with beginning-level students in mind, this website provides brief grammatical explanations and straightforward exercises.
Conjuguemos: Practice verb conjugations for many tenses in the Spanish language. The website is presented in a drill format, where verbs and subject pronouns are provided for you to conjugate appropriately.