New version of Novell Suse Linux v10 is out and available free for download (w/o support).
If you need support and updates then you can buy Suse Enterprise 10 from same site. I am currently using Suse on P4 laptop and it works nicely. You can purchase both Desktop ($50 better than RedHat ws 4.0, IMPO) and Server edition
More info at: Novell Suse Linux web site.