From this site:

select @@VERSION

exec sp_server_info

SELECT SERVERPROPERTY(‘ProductLevel’)

  No SP
(RTM or Golden)		 SP1 SP2 SP3 / SP3a SP4 SP5 SP5a
SQL Server 6.0 6.00.121 6.00.124 6.00.139 6.00.151       
SQL Server 6.5
(Hydra)		 6.50.201 6.50.213 6.50.240 6.50.258 6.50.281 6.50.415 6.50.416 
SQL Server 7.0
(Sphinx)		 7.00.623 7.00.699 7.00.842  7.00.961 7.00.1063    
SQL Server 2000
(Shiloh)		 8.00.194 8.00.384 8.00.534 8.00.760 8.00.2039    
SQL Server 2005
(Yukon)		 9.00.1399.06