Like the topics says, I'm new to this,
Right now I'm using a circa '97 455 mhz celeron HP with 192 mb of ram...
Besides the obvious (to switch to a much, much newer, nicer rig which I plan to do soon ) are there any suggestions?

In particular any pointers on practicing before i switch, what to switch to, and anything else that helped you.
I like Ubuntu and fedora Linux distros so something compatible with these would be great; I'd hate to have to go crawling back to Microsoft and my mac is a g4 imac that I'm not root on... so something wine compatible or that runs natively on Linux would be amazing.

At any rate please excuse my ramblings and please give me advice.
Thank you!

While your particular box is going to take ages to render out anything remotely complicated, my recommendation based on your software set-up is to use Blender. You should be able to find it in the Ubuntu repositories easily. Blender will run natively on Ubuntu, and works excellently for both modelling and rendering. Some people do prefer external renderers for Blender, which are available.

Blender has a very steep learning curve, but once you get past what can occasionally look like the inside of a fighter jet, it's fairly simple and easy to use. There are dozens of excellent tutorials out there, both video tutorials and written ones. I would highly recommend starting out with the book Blender: Noob to Pro. It walks you through the interface and some actual applicational tutorials.

I would also get yourself a download of The GIMP, which should actually come pre-installed with the latest release of Ubuntu. It's the open source equivalent of Photoshop, and you'll want it for cleaning up your renders.

Thanks for the advice.
I'm really getting about ready to use this computer as a doorstop.
My old computer died on me and it was kind of old anyway, so I'm just going to build a fast rig to model and play spore on.

Btw what do you mean cleaning up my renders?
Is that to ev specific(to create masks or something) or more general.

You'll generally want to render sprites, at least, twice as large as they need to be, then apply an unsharp mask and resize in the GIMP. Blender also sometimes leaves rendering artifacts, and you can edit those out, or create masks with the GIMP. You may also just want to apply filters over your image to give it different textures and the like.