What are the default Fn-Key Functions?

I've got a MacBook Pro running OS X 10.6.8.

Does anyone know what the default settings are for the function keys (say, if you are using the Finder)?

For example, what's supposed to happen if you type Fn-1?

I've figured out a few (Fn9-12), but want to know what the other function keys are set to do.

Second question -- just as important -- is there any way native to OS X to reassign the function keys' functions? (or if not native to OS X --without having to use a script or something-- is there third-party software that you recommend?)

(I found an Apple webpage discussing the Fn keys, but the content of the discussion is not available: currently "under maintenance.")

First google results:

'Mac function keys'
Mac OS X keyboard shortcuts

'Re-assign function keys mac'
Mac OS X: How to change the behavior of function keys

This remapping program does what I need.
(Documentation is a little thin, but the program works well, and it's free.)
KeyRemap4MacBook