[G4] Where have all the gigs gone?

[Davis Gaffga]

A little over a week ago I upgraded my Quicksilver Mac from Panther  
to Tiger. With Panther I had a little over 14 GB's free on the 40 GB  
disk on which it was installed. After installing Tiger (I did the  
easy install) I now have only 5.5 GB's available.

I knew Tiger might eat up some more Gigs, but nearly 9??

What can I do to regain some hard drive space?

         Thank you in advance..