Resources & References

Bartertown is a community, miniatures and game trading site. Members can post For Sale and Wanted ads with each party working out the specifics of a transaction on their own. Caveat Emptor. Other than peer ratings, I'm not sure what other safeguards are in place to protect you from a bad trade experience, so do your homework.
Brushthralls started out as a Warmachine-oriented painting site, but the four founders decided to expand beyond the world of Privateer Press and now address miniatures, paints, and equipment from other manufacturers. Brushthralls has a wealth of great articles, nicely written and supported by photos, spanning all aspects of painting.
Dakka Dakka is another large online community. They have a nice articles function that you can use to find various articles on painting, tactics, army composition, etc.
Librarium Online is another large online community, primarily dedicated to Games Workshop games, but with sections addressing other games. They have a nice selection of newbie guides.
TerrainGenesis has been around for as long as I can remember. If you're looking for an article on terrain making, it's probably there at TerrainGenesis.
Terrain Thralls is another excellent terrain-making resource, though as the name implies, they are mainly focused on Warmachine- and Hordes-themed pieces.
Warseer (formerly Portent) are my standard forums. They have an active For Sale and Wanted section as well as extensive discussion forums, mostly about Games Workshop-related games, but also Warmachine and some others.
Dice Troll (formerly BlackOrc) is another community that been in and out of. It's a smaller community, but friendly. One of the features I really liked was a gallery section where you can post pictures and receive feedback and comments.
Bolter & Chainsword is another lively internet community. Their page has a great section on army painters that you can use to try out a couple of color schemes before you put brush to figure.