Mango Languages is an interesting site that has just begun. It provides free self-directed and bilingual online language courses,  including ones for English for Spanish-speakers and English for Polish-speakers.

You have to register, but it literally takes seconds to do so.  I don’t think it’s the best web application out there to help Spanish-speakers learn English, but it’s probably worth a visit.

I have the link on my Bilingual Exercises page under Spanish.