how do i play

i have been tryin ur method but it fails because i have a mac plz xplain how to with mac

You can find the %appdata%\.minecraft directory on a Mac by following something like this:

Yourusername - (Possibly Users next, not sure) - Library - Application Support - Minecraft

From there just continue with the rest of the guide.

Here's how:
Go to finder.
Hit Command+N (opens new window)
Are you in your user Directory? You should be, if not get to there!
From said directory, double click on the "Library" folder.
Now, double click on the "Application Support" folder.
Scroll down and find a "minecraft" folder. Double click on it.
See a "bin" folder? Good! Open it (double click).
Now, move the "minecraft.jar" already in there to your desktop (or just delete it).
Now, you need to move the minecraft.jar that you got from Orcworm.net or another source into there. ONLY MOVE A "minecraft.jar" FILE INTO SAID "bin" FOLDER. DO NOT DELETE/MOVE ANY OTHER FILES IN "bin" FOLDER!
Now, start up minecraft and enjoy!

Updating:
Simply delete the ENTIRE CONTENTS of "bin". Then, rerun minecraft. Your saves are safe AS LONG AS ALL YOU DO IS EMPTY "bin" ONLY.

At any point, DO NOT DELETE THE "minecraft" FOLDER OR IT'S CONTENTS, ONLY THE "bin" CONTENTS MAY BE TOUCHED!

So there you go! Have fun!