As for the actual hats themselves and not just the mod, you can add them yourself and other people will see them, even if they don't have them (they download it on the fly, as long as that option is enabled.) You can get them from
http://techne.zeux.me/ and put the tcn files in the \minecraft\hats\ directory. Then pick it from the menu in-game. To place the hats on the ground as I've seen them do in DW20's videos, you also need the Hat Stands mod which is linked along with the Hats mod on iChun's site. (
http://ichun.us/)
