i am new um what is it anyone kind to tell me?

It's Jazz Creation Station, the program to make levels with for JJ2.

It comes with all retail versions of Jazz Jackrabbit 2. Illegal downloads however tend to be incomplete, most of the time that JCS is missing from them.

- JelZe GoldRabbit =:3

I don't have the Macintosh version of JJ2, but I heard that the Mac version doesn't come with JCS. Another reason why there are so few Mac Jazzers.

uh....do i need it?

You do if you want to make your own levels. And yes, the Macintosh version doesn't come with JCS, nor do any Shareware Demo's. You, on the other hand should have it if you have full version 1.20 of higher. If you downloaded a full JJ2 game off the internet, chances are you got version 1.00g, the OEM version, which is a pre-release shipped with PC's, which doesn't come with JCS.

- JelZe GoldRabbit =:3