Every week, WoW Insider brings you Gold Capped, in which Basil "Euripides" Berntsen aims to show you how to make money on the auction house, and Insider Trader, which is all about professions. For Gold Capped's inside line on crafting for disenchanting, transmutation, cross-faction arbitrage and more, check in here every Thursday, and email Basil with your comments, questions or hate mail!
The Undermine Journal is an invaluable site that a lot of auctioneers have been making great use of. I wrote about it when it was in alpha, as well as how to use its market alert to watch for cheap deals. Unfortunately, the days of having a convenient graph showing you the price history for your realm are numbered. There's a very real possibility that this service will be killed by Blizzard's new auction house interface, and we'd be back to each keeping our own spreadsheets.