The most acclaimed program for learning English for non-English speakers is Rosetta Stone. A free trial of Rosetta Stone is available at RosettaStone.com. Rosetta Stone uses immersion to help students learn a new language, starting out with language basics and progressing to adult fluency as the learner improves.
A comprehensive beginner's course in English for non-native speakers is available through Learn-English-Online.org. Unlike Rosetta Stone, the whole course is available for free.
Free printable resources are available at Usingenglish.com; their games, flash cards, example conversations, homonym lists, reading passages and worksheets can help non-native English students retain and practice what they learn.