If you order Mac OS X 10.4 Tiger [DVD] from Amazon, you can get a $35 rebate. Not a bad deal. I ordered Panther online and it was shipped to arrive on the date of release, so I got it the first day. Apple's got a list of 200 new features in Tiger. I heard from Glenn Fleishman today that the Tiger edition of his Take Control of File Sharing ebook is available for pre-order, to ship on April 29th, when Tiger ships.