LingQ.com (Web based service with tutoring. An account costs US$ 10 per month).
lingro.com (An on-line environment that allows anyone learning a language to quickly look up and learn the vocabulary).
readlang.com (An on-line service where you can import articles, read and translate them, and learn new words. Price: US$ 5 per month or US$ 48 per year).
Resources for various languages
GoogleDocs Spreadsheet with recommendations for LWT Language Settings ("Templates") Important: Please be careful when making additions or corrections!