[Wolves] how low can Linux go?

[baza]

As part of this community project I'm working on we want to install 
Linux (Ubuntu) on donated PC's. This is to save the Microsoft licence fee.

An issue we need to work out is what is the MINIMUM speck Linux will run 
on, using Gnome? Most of the business donated PC's are running 64meg 
ram, which I figure is way to small. But to keep costs down we don't 
really want to have to convert them into 'Uber Boxs' to run Linux.

So, what is the smallest hard drive and RAM we can get away with?

Baza