I'm continuing to build my compilation of all the WotLK leaks I've seen thus far. There are currently two main sets, or albums: 1st WotLK Leak - 4.20.2008 and 2nd WotLK Leak - 5.17.2008. The albums are always growing as the internet produces more leaks.
The 2nd album will be updated with leaks throughout the next few days before I add a 3rd album with new leaks.
The current flow of leakage is said to have happened because the Friends and Family Alpha testing for WotLK began very recently.
UPDATE: I added a cool new picture of weapon loots in WotLK to the compilation.