You can write in Query window to find which version of SQL Server 2008 is running ?
SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')
(or)
SELECT @@Version
Microsoft SQL Server 2008 Service Pack 2 (SP2) is now available for download.
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=8fbfc1de-d25e-4790-88b5-7dda1f1d4e17
Version Build
-----------------------------------------------------
Service Pack 2 for SQL Server 2008 10.0.4000.00
Service Pack 1 for SQL Server 2008 10.0.2531.00
RTM 10.0.1600.22
