Do you know how i can download Emuhacker for 2.3.0 ?
Depends on the version you want. The current latest (13th December 2007) is the one for WoW 2.3.0 Beta 4. WoWEmuHacker for 2.3.0 Beta 4 download

If you are looking for other versions. Have a look in the whole WoW private server hacksection: WoW Hacks download