It's designed for Spanish-speaking adults and has three primary paths---one for beginners, one they call "Second English Class", and a third for practicing English speaking and reading. Once you register, you can keep track of which lessons you've taken, and the program even shows your score for each class. And it's all free. We like that.
You can also specify whether you want the instructions in English or Spanish, which is extremely helpful if you're just starting out.
There's an ESL thread in the Continuing Ed. Forum. Check that out too, or make a new one.
Other ESL Help:
- Learn ESL Through Movement
- How to Learn a New Language on the Internet
- Learning New Languages with Cartoons
And of course, remember to visit the ESL site at About.com!