Mat Cusick, Teacher, Writer, Founder of Q Arts Foundation, Research & Develop
I have experience teaching English to Spanish-speakers in Mexico, and have collected some of the resources I have found useful on the blog for my classes: mazunteglish.tumblr.com.
Comic books, as others have noted, are a great resource. There are many that can be found online in various languages, which is especially helpful—for instance, the anime series, One Piece.
Children's picture books are great, too, especially the new phenomenon of bilingual picture books. Monica Brown's bilingual English-Spanish books are great, as are the books of Juan Felipe Herrera, and the poetry books of Francisco X. Alarcón. (Here's a list of Spanish-English bilingual books.) Infinity Auto Insurance created a website with free Spanish-English bilingual books and app downloads, called Read Conmigo.
Movies, television, and other videos with subtitles are a great resource. Most TED talks on the TED.com website not only have subtitles in a variety of languages, but also an interactive transcript. Kinetic typography, which animates a spoken text, is an interesting new way to make reading more engaging (as in these videos featuring portions of speeches by Martin Luther King, Jr.) Reading along to the lyrics of a song can be a very engaging way to learn to read English, and there are many resources to make that experience an even richer learning opportunity, including lyricstranslate.com, for finding song translations, and lyricstraining.com, which turns music videos into a game of textual karaoke.
There are also some very interesting online resources that can help students learn while they surf the web, through Chrome Extensions: Instant Translate, which provides word translation on any page just by double-clicking; Language Immersion for Chrome, which works in reverse, randomly translating words on a page into a target language for reading practice, then translating it back with a mouse-click; and Lingua.ly, which provides online articles in a target language, translates unfamiliar words into a native language, and allows readers to save words to a database for later vocabulary practice.