-NDS- Action replay code making

I want to learn how to make codes...
I am a Mac user so... ( Figure out that lol )
Where do I start off?
Is their a particular site I need to go to?
Does it cost money?
Is it complicated to learn?
Etc...

If you want to learn ARDS Code Types (something I need to study <.<) go to this link:

http://game-hackers.com/threads/85-N...play-Codetypes

If you want to learn ASM, learn from Siestacat's Site:

http://www.siestacat.wordpress.com/

For Tools:

http://game-hackers.com/threads/738-...ols-Collection

I made an ASM Tutorial...it might not be so good, but:

http://nintendq.ephpbb.com/ar-code-c...ial-t43.htm#65

You might need to sign up to that site to view that post though.