Microsoft was quick to respond with an apology and somewhat comforting news that this bug will not affect how SharePoint functions until the expiry date has passed (180 days from the service pack install). They also said it will have no impact on customer data, configuration or application code.
While a hotfix is in the works, you can now get a manual workaround to resolve the problem. Note this was the most popular link in the blog announcing the bug. The fix requires SharePoint Admins to re-enter their product licenses numbers in the Convert License Type page in Central Administration.
The bug affects Office SharePoint Server 2007, Project Server 2007, Form Server 2007, Search Server 2008 and Search Server 2008 Express, but not Windows SharePoint Services 3.0.
Microsoft is still encouraging organizations to install the service pack. You just also have to apply the manual fix to the expiration date at the same time and you'll be on your way.