Spanish 
General Websites
Rosetta Stone
Spanish Language -- From About.com
Specific Aspects
Como Usar el Internet -- Guia tutorial para el uso del Internet
Internet Terms in Spanish and English -- Glossary, from Lingolex.com
Mexmaster -- Mexican search engine
Spanish Dictionaries -- From the Web of Online Dictionaries
Terra -- Search engine from Spain
Library Related Sites in Spanish
Learn the Net (en Español)
SOL -- Spanish in our Libraries
Listening Sites
Learn Spanish
Aula Diez
Spanish Listening, Speaking, Pronunciation
Spanish Grammar Excercises