Here is an updated compendium of interesting flying related sites, new ones listed first...
Darren Smith's site Alternate Link. This site has some great training resources, and a really interesting and complete weather section.
CSC DUATS Golden Eagle FlightPrep. Great free flight planning software for your PC.
Whittsflying. What it lacks in format, it more than makes up for in content.
pad39a, good list of aviation related links.
NOAA's National Weather Service Aviation Weather Center Aviation Digital Data Service (ADDS). Weather, straight from the source.
AirNav - all the information you need on airports, navaids and more.
David Megginson's Land and Hold Short.
flyagogo.net. flyagogo.net provides the aviation community with the most easy-to-use, interactive and graphical online flight planning tools, aeronautical charts, live weather, and aviation database available anywhere on the web. No registration, no proprietary plugins required, works with any modern web-browser on any platform.
Aviation Acronyms and Mnemonics (Check out his other cool aviation stuff at http://www.scottsasha.com/aviation/)
Tim's Air Navigation Simulator www.visi.com/~mim/nav/
Listen to live Air Traffic Control on your PC at www.liveatc.net/
Digg It!
Bookmark it!