hi julio.

for addons, i have to recommend WoWAceUpdater
http://www.wowace.com/wiki/WinAceUpdater

as for using keyclone, it depends on how you are using it.

you should read this entire page:
http://www.solidice.com/keyclone/tutorial/index.html

now... assuming that didn't help, do this:

first make sure your wow session is in windowed mode.

then, run both wows.

log in. stay at the character select screen

run keyclone. if you are using vista... run keyclone as administrator

by default, keyclone will automatically add any wows you have running. as such, you should now have 2 'World of Warcraft' entries in the keyclone list.

click on your main screen

hit enter

both characters should attempt to enter game at the same time.

once you are in-game... hit spacebar. both will jump.

you are multi-boxing. any key pressed in one will go into the other.

next, you'll have to figure out the keys... but that's a personal preference.