targeting question.

ive got a question regarding targeting enemy players/NPC's in world of warcraft.
i can get my toon to pretty much do everything my main can do, however he wont target what my main is targeting.
can any1 help me out on this? are there perhaps any addons?
or should try to mouse map something in the form of a macro?

manny thanks in advance. ^^

Do a search for "target macro".

i see thanks :)
1 more question.
would it be smart to make this macro on my alt and map the macro key to the left mouse button?

You should just go ahead and try it and see if you like it... if you don't, put it somewhere else.