The World Wide Web Consortum develops and maintains standards for Internet protocols. Excellent reference for expert programmers (not for the young learners!)
W3 Schools is devoted to making instructional sites for coding by various W3 standards. The "quick 'n dirty" version of the W3 standards, easier to read, find, and search than the actual standards whitepapers, but not always completely up to date or completely extensive.
Open Source Related
KernelTrap: news site about the Linux and *BSD kernels. A lot more fun than grepping through your mbox archive of the various kernel mailing lists for important info.
The GNOME Desktop: an open source suite of software designed to provide a good desktop experience while also providing a suite of developer libraries to integrate applications further into the desktop.
The Mono Project: an open source implementation of the .NET framework. Provides a whole host of programming languages that can be compiled and run as managed code with the Mono runtime. As with most open source projects, it's a work in progress, but it's really taking off these days (I currently write a LOT of C# code). See the Banshee Project for an excellent show of it's capabilities.
FreeDesktop.Org: dedicated to supporting unification of free desktops (including Gnome, KDE, etc) by providing ground for setting standards, as well as hosting various software projects.
The Linux Documentation Project: a great resource for all the little HOWTO's that you'd ever need - from compiling a linux kernel, setting up various system services/daemons, to making grilled cheese. A lot of the documentation is showing it's age but it is a great collection of resources.
Other Places Relating to Me
Sting, my trusty webserver/firewall/network server. Named after Bilbo/Frodo's sword that glows when the orcs are near, this box keeps both itself and my other computers safe and sound. It also provides a few public services that my ISP hasn't discovered yet. Unfortunately I cannot run my webserver on port 80 - so it's on port 8000. There you will find links to a ViewVC of my local subversion repository, and a nifty patch browser that I put together for when I want to host a patch.