Not sure if there are production environments still working on the legacy of SQL Server 7.0 version. But it is worthwhile to start considering to move ahead. The extended support also finally ends now. Support for SQL Server 7.0 will end on January 11, 2011. Microsoft is ending support for this product as part of our Support Lifecycle policy, found in http://support.microsoft.com/lifecycle. SQL Server 7.0 will no longer receive assisted support or security updates from Microsoft after the end of support date. Self-Help online support will continue to be available for a minimum of 12 months after the product reaches the end of support. Self-Help options include public knowledge base articles, FAQs, troubleshooting tools which are typically available from http://support.microsoft.com and the Microsoft Download Center.
For more information, refer to http://blogs.msdn.com/b/sqlreleaseservices/archive/2010/09/29/end-of-support-for-sql-server-7-0.aspx.
Also, in 4 months (Apr 2011), mainstream support for SQL Server 2005 (RTM version) will end (this means no more hotfixes/Cumulative Updates after that unless you have an Extend Hotfix Support agreement). Review the lifecycle link: http://support.microsoft.com/lifecycle/?p1=2855 for additional information.