Where to save classes? How to access classes?

[David Mitchell]

Hi,

I'm trying to get into the object oriented aspect of Python. If I create 
a custom class (in it's own file), how do I access that class in a 
function in a different file? In Java there's the notion of a CLASSPATH, 
where you can tell the compiler to look for classes. Is there something 
similar to this in Python?

Thanks,

Dave