Not sure how to uninstall correctly.

Kay, I'm a total newb when it comes to not only this mac but forum threads!

I've trashed all of my adobe CS3 stuff to make room for trial DL of CS4.

Well, I've trashed a whole SUITE worth of CS3 and I've only installed one Photoshop CS4.

when I got to open CS4 it tells me I have not enough memory RAM.

I got my Macbook Pro in August and I really don't know much...

I'm trying to finish projects for school and Ahhh everythings a mess... what do I do?

I just read this form the Adobe webpage

IMPORTANT: Mac OS has new uninstall functionality. DO NOT drag applications to the trash to uninstall them. To safely uninstall on Mac OS X, double-click the product installer in Applications/Utilities/Adobe Installers. Authenticate as an administrator, then select Remove Components and follow the on-screen instructions.

What do I do!!! I think I totally wrecked everything!

I think that the installer files should still be there and you can still delete the remaining core files.
Do you back up your computer?
Next Time you could try using a Program called AppZapper and It deletes the whole application and all the system files along with it.

I'm still trying to find the installers, but I'm having issues.

All I have for backup is an 8gb Flash drive. I don't have any external drives yet.

How does this AppZapper work?

I found the installer!! Thank you for replying, it means a lot.

I think I'm able to clear this mess up!

yep.
Your Welcome!
I suggest getting a external
You can get one at a local best buy for like 80$ and that would be a 320GB HD

Its a no brainer if you dont have one.
Its a Must in the World Of technology and how important your files are to you