Games
Faldon - Faldon is an online RPG I wrote, and am presently rewriting the client to (detailed in my Development Journal). The game has some flaws, but I encourage you to try it.
Useful Libraries
Apache Portable Runtime - APR helps keeps a server portable, and has handy functions for safe path manipulation.
cURL - cURL is a reliable HTTP library.
Percival RSA - The smallest RSA implementation I know of. Floating point, so check your rounding mode.
SDL - SDL abstracts video, input, etc., allowing one to avoid tedious low-level coding.
SQLite - This is a *great* featureful and free embeddable database engine.
Squirrel - Squirrel is a nice object-oriented scripting language.
TinyXml - TinyXml acts a lot like .Net's XmlDocument class. For an XML library it's pretty small (140KB), and the speed is adequate.
XmlRpc++ - XmlRpc++ is a compact, functional XML-RPC library.
Useful Programs
NSIS - NSIS is an installer builder from Nullsoft, the creators of Winamp. It supports BZip2 and 7-Zip compression and produces EXEs only a few kilobytes larger than a raw archive.
Programming Sites
Chris Hecker's Website - Chris's writings on game design are very insightful. Not updated very often.
lw-plugin - Go here if you have any questions about writing plugins for Lightwave 3D.
Molly Rocket - One of those rare coding forums where the programmers are actually competent.
MUD-Dev Archive - MUD-Dev was a list server full of thoughtful discussions about online RPGs. I have it archived on this site.
The Inner Product - This site has many interesting ideas and articles. Sadly, it hasn't been updated recently.
Miscellaneous
Illumination Pit - Zammbi has lots of nice rendering art on his page.
Spectre's Software - Aaron has a lot of good games and utilites here. Have a look.
Yet Another Blog - Crovax is a good friend and a GM on Faldon. This is his weblog.