yer AHK rocks, i've been using it for a while now.
The thing to watch out for is the macro takes preference over nearly all other keys when its in use. So the one i have when u press left alt it makes you jump strafe prone, the macro wont be overridden by BF2, where alt is toggle 3D map.
It is pretty easy to change the key you want the macro to do something with.
If your script is not an .exe yet, you can open it with notepad.
Then all you need to do is find every instance of the key and change it to the new key you want.
So,
if i was sick of having the "Jump,Strafe,Prone" as left alt, and wanted to change it to left ctrl, i would:
Open the script in notepad.
Press ctrl+F to open the find dialogue box
type in L_alt
for every instance of "L_alt" change it to "L_ctrl" (they may be lowercase L's)

then save the script.
AHK is good because it tells you when you've done something wrong when you try to run the script.
So if the button in the macro is the same as your favourite aimbot button, then open the script you downloaded and change every instance of the aimbot button to a new button.
Some scripts will make a beep to let you know that the function is active.
Frub