The best way to learn a new language is to immerse yourself. Below are some ideas on to improve your speaking, listening, writing and reading.
Language Specific
SpeakingSharedTalk - language exchange community
http://www.sharedtalk.com
The Mixxer - an educational site hosted by Dickinson College for language
learners and teachers to find a language partner for a language exchange via Skype.
http://www.language-exchanges.org
Polyglot - find a language exchange partner
http://www.polyglot-learn-language.com
Your language exchange community
http://www.mylanguageexchange.com
ObBio - The International Community for Conversational Languages
http://www.obbio.com
The Penpal Network
http://www.penpalnet.com
Tandem Server Bochum - language learning exchange partnerships
http://www.slf.ruhr-uni-bochum.de
italki - online language exchange and resources for language learning
http://www.italki.com
Meetup.com - a way to meet people interested in learning languages, etc.
http://www.meetup.com
Speak Mania - find penpals for language exchange
http://www.speakmania.com
Huitalk - a community for people learning languages
http://www.huitalk.com
Etudiants du Monde / Students of the World
http://www.studentsoftheworld.info
AskLingo - the free language exchange site
http://www.asklingo.com
BePolyglot - an online community dedicated to creating multilingual speakers
http://www.bepolyglot.com
Livemocha - Learn Languages and Practice with Native Speakers
http://www.livemocha.com
Language Exchange Project - a simple and intuitive website to find a language exchange partner, pen pal or friend
http://www.language-exchange-project.com
Palabea - the speaking world
http://www.palabea.net
Penpal-Gate - Language exchange, meet penpals
http://www.penpal-gate.net
Scrabbin - language exchange
http://www.scrabbin.com
Lenguajero - a language learning community for English and Spanish speakersbr />
http://www.lenguajero.com