There's a really good (IMO) guide
here, which I have used as inspiration for my locks gear (although I'm not at lvl 70 yet). It has an explanation of which stats are best for a lock, and then it lists good gear at lvl 20, 30, 40 etc. up to 70. There are many alternatives listed for each item slot, and lvl 70 is divided up into basic lvl 70, heroics, kara, gruul etc. There's also socketing and enchants suggestions.
There's also
this site. It details which 'warlock' items are dropped where, and there are lists with different options for wands, boots, rings etc., depending on spec (under the heading 'sample specs'). I have only found this site the other day, so I haven't really used it yet, but it seems great so far.
As a tailor, you should look to the
frozen shadoweave set, perhaps complimented by spellstrike or battlecast (depending on spec and PvE vs. PvP). You can see the details as well as the mats at the link. FSW is reasonable simple, you mostly just need shadoweave, imbued netherweave and lots and lots of primal water. Spellstrike and battlecast are more expensive, and they all need a primal nether, which drops from bosses in heroic instances, and if you're lucky from bosses in high-end normal instances.