Sadly, it seems the CRZ exploit has been fixed as of 6.0.2. The really short explanation is you used peerblock and a noodle cart to farm on pretty much any server you wanted.
The longer explanation is you used peerblock to prevent your character from leaving the realm its currently on. Because cross realm zones are hosted on any server within a battlegroup you could feasibly have 6 or 7 different servers to check without using cross-realm grouping (which would theoretically let you check all servers). First you'd scout out Storm Peaks by taking the flight path to Ulduar from any zone in northrend that wasn't also hosting Stork Peaks. (For example, Crystalsong could be hosted on Sargeras, Storm Peaks on Area 52, Icecrown on BDF, etc). You wouldn't actually change servers until you land so this was a good way figure out if Vyragosa or the TLPD was up on a given server.
When you finally found TLPD up on a server you'd figure out the IP of the server hosting Storm Peaks was and block that. Now you're no longer a going to be moved cross realm. You'd get spammed with "Instance transfer failed" or something like that, and the zone would be completely empty of anything spawned server-side (NPCs, fishing pools, etc). I'm not sure the actual reason, but for ease of explanation, let's say that everything was in a different phase from you.
The trick was when you used a noodle cart you were put in the same phase as all the NPCs so you could actually see them. You had about 1.5 seconds or something to tag whatever it was you wanted to kill and then you had to finish it off with indirect damage (blizzard, consecrate, DND, etc) because you could no longer see it or target it once you were fully out of the noodle cart. There's only a few spots where you could reach TLPD from the ground, and even then it was max range for most classes (I could barely reach with judgment). You'd have to drop another noodle cart to loot it after you killed it (and hope you didn't accidentally kill it and it slipped halfway down a mountain or someplace you couldn't reach from the noodle cart).
Aeonaxx was a bit more technically difficult and required a bit of luck. Same principle (block the CRZ hosted realm's IP) but because Deepholm is its own instance and not connected to anything you had to get creative when you zoned into it. Somehow someone figured out if you let the loading bar get to ~80% when leaving a battleground and THEN turned on peerblock you would be zoned into your realm's instance of Deepholm. The downside to this is you could only check YOUR realm so if your realm was the host of the CRZ Deepholm you were fucked. It was very tricky to time it just right, but I was able to do it twice (once for me, once for a friend) out of probably 10 or so tries.
Anyway, TLPD is supposedly fixed. Aeonaxx may not be since it doesn't require noodle carts and the noodle carts phasing you and allowing you to see local NPCs is what was fixed.
