How to identify your SQL Server version and edition

For SQL Server 2005:
SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')

For SQL Server 2000:
SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')

For SQL Server 7.0
SELECT @@VERSION

For more information: read here