Recommended Links

Languages

Learn French by Podcast An excellent podcast for those who already know a little French but need some practice.
Livemocha A social network for learning foreign languages. Includes self-paced lessons and opportunities to work with native speakers in a variety of languages.
lernu! A very good website for learning Esperanto. Lernu is very much like Livemocha in that it combines self-paced lessons with one on one interactions with users from all parts of the world.

Java APIs I have never been fond of the design of Sun's Java website, but there is no doubt that convenient access to the APIs is indispensable. This link is to a list of APIs, not to a specific API, so hopefully it will stay current as new versions are released.
perldoc.perl.org Core documentation for Perl in HTML and PDF formats. A simple, but wonderfully useful site.
PHP.net A useful resource for programming in PHP so long as you remember to check the 'Installing/Configuring' requirements for a function before using it in your code.
Regular-Expressions.info Everyone who works with information should know the basics of regular expressions.

YouTubeVideo clips of obscure musicians, old tv shows, cute kittens, and everything else you can think of.
Facebook Some people believe that Facebook is a tool for meeting new people and strengthening professional connections. I consider it an excellent place to play Lexulous and other word games.