Your study of the language should be driven primarily by a recommended Language Learning Program that provides a sequence of lessons. However, you will probably encounter concepts (i.e. gender of nouns) or specific words within those lessons that you'd like to gain a better or deeper understanding of. For that purpose, you should keep a few language references handy that you can refer to as needed.
Pronunciation
Language Concepts / Grammar
Spanish-English Dictionary / Word Reference
When you need to look-up the meaning/translation of a word, or find examples of how it is used in a phrase or sentence in various contexts...
Spanish-English Translator
Sometimes you just need to "cheat" a little. An automatic translator can be very helpful in some contexts, but it can easily steer you wrong. Be careful! Language is extremely complex, and translation between languages often requires context. Use computerized translators at your own risk, and never assume that the results are accurate, because they frequently make mistakes. If you doubt that, experiment with converting sentences or paragraphs from English to Spanish and then back into English again, and see what you get. :)
