OS X on an original Tangerine iBook

[Spike T Frog]

Hi,

I am looking to upgrade my other ibook, an original tangerine version, 
up to OS X.  I have the original hard drive .  I understand that this 
will work, but with modest performance and limited screen size.  If I 
were to do this, how much hard disk space would I use just to get OS X 
installed?  Or, what can I cut out of a typical installation in order 
to maximize disk space?  Excel, Word, Mail, and Safari are the main 
applications that I use.

Thanks in advance everyone,

Wai Lee