Will Windows XP Sale effect Windows 2000

Windows XP is scheduled for shipment in October of this year I beleive. Will Microsoft stop selling Windows 2000 at that time. What if a company wants to upgrade to Windows 2000 and has not done so. Will they be forced to upgrade to Windows XP ifthey have not purchased Windows 2000 by the time Windows XP Ships. This will also effect what certification to seek. Why would I bother to do 2000 if Microsoft will no longer sell it. I know there are a bunch of companies that have not upgraded to 2000 yet.