These are based in turn on AH scanning tools like Auctioneer, which you use to scan the auction house; and get recent pricing.
Bread and butter for established auction house players. But...., we have new tools available. First of all the auction house scan has been 'bettered' by The Undermine Journal. Something that scans the AH hourly; every day; does far better than I can with my intermittent scans; plus it is much faster and doesn't consume my in game time.
There is also the auction house API. It provides auction data (faster than I can scan inside the game) by item id, recipee lists (by item id, including recipee names) and names for items. This is nearly enough to make an out of game profitable crafting tool. What I am missing is an easily updateable, usable in a program, list of recipee and material items listing item id's.
The following websites (among others) have lists
The tool that I am looking at building will be a tool for someone with my skillset (fairly technical, not much in the way of pretty user interfaces); but would be very easy for someone with a flair for UI's to either build upon; or use the design to re-implement. This also is a project I would much rather someone else have written (rather than have to write it myself). What I don't want to do is manually re-type data that Kaliope or DB-champion have already discovered.
What I would ideally love is a WoW API that returns the materials (including duration of cooldowns) of crafting recipees (and no - the current recipee API returns recipee name but not materials). Failing that, a similar web based request to other reputable websites returning data would be good.
If we can put this last piece in the puzzle, we should be able to build a tool that shows us what is profitable, and what is not.