First, a little disclaimer: This guide requires that you be a rogue between levels 69-80, although level 70+ works best. You also need Wrath of the Lich King expansion pack. Oh, and being Horde helps in terms of transportation, but it doesn't help the farming at all.
Ok, now that the disclaimer is up there for everybody to see clearly, I don't want anybody talking about how I didn't say it was only for rogues with WotLK.
1) Find some way of transportation to Dragonblight, which is on the Northrend continent. If you are horde, fly to venomspite, if alliance fly to Wintergarde Keep.
2) Directly south of Dragonblight and Wintergarde, is the Scarlet Crusade's camp of "New Hearthglenn." Go here. You know you are in the right spot if you see lots of humanoid mobs.
3) Being the rogue that you are, you are going to stealth once you get into the area with the mobs. If you somehow pulled them and they are attacking you, use vanish. You shouldn't need it later on.
4) Once stealthed, make sure that you have: Distract, Sap, and Pickpocket all on your main bar.
5) Begin farming! Walk to the mobs, sapping if they are alone and distracting if there is more that one. Once you don't have their attention, pickpocket them. Every mob drops about 10 silver and some odd thing, like a junkbox or a pr0n magazine. (No, really.)
The grey items that pickpocketing them drops sell for about 7 silver a piece.
In case you don't believe that this is good, quick money...
If you pickpocket 10 mobs in a minute, thats 1 gold a minute (Keep in mind 10 silver is a rough estimate. Some drop more or less this amount.) 1 gold multiplied by 60, is 60g per hour. Without killing anything (Not even any hard work), at an average you could be making 60 gold per hour. That sounds pretty good to me!
Thank you for reading my guide, and I hope you will use this money to your advantage!
P.S. I, Hallowsend, DID, write this guide. It is d3scene's guide, and is not to be placed elsewhere without our permission.