Oxford Picture Dictionary (for all ages)
  Dorling Kindersley Children's Illustrated Dictionary (for kids)

• Richard Scarry's Best Picture Dictionary Ever (for kids)
  
• Cat in the Hat Beginner Book Dictionary (for kids)

Other Links

• WannaLearn "English as a Second Language (ESL)" Page - free online tutorials and other ESL learning resources.
• WannaLearn "World Languages" Page - free online tutorials in a large variety of languages.
• English Forum - resources for students and teachers of English (ESL/EFL). Includes interactive exercises, message boards, school guide, Web directory and more.
• Yahoo! "Specific Languages" Page - huge directory of multilingual language learning sites.
• Power-Glide Language Courses - Revolutionary language courses for children and adults, available for French, Spanish, German and Latin. Read WannaLearn's review of Power-Glide.