rpms will put the files where they belong.
bzips need to be uncompressed, and untarred in the directory you want the files in.
http://rpm.pbone.net
go there and you need kernel-source-2.4.20-8.i386.rpm.
(do a search it comes up with links to download.)
its an rpm all you need to do is install it.
Thats the sources your looking for .