How to know SQL Server version and Edition

some time we just install the sql server , but still we don't know which type of version it is and edition also , basically we need that when we are upgrating current version of new version. Current there is sql server 2008 is there in market,

now how to determine which version of sql 2008 is running out machine,
- run the following T-SQL statement,

SELECT SERVERPROPERTY ('productlevel') ,SERVERPROPERTY('productversion'), SERVERPROPERTY ('edition')

you will get the result like :
RTM | 10.0.1600.22 | Enterprise Edition

RTM is product level which means - 'Release To Manufacturing'.
but what is means of RTM - is a stage on which the distribution of process begins CD of
that product get created and retial packs and then product will get shipp , this is very
long process and because of that RTM date is mostly ahead of the final release date.

10.0.1600.22 means product version.

Enterprise Edition means its a Edition there are some other editions are also there like
Developer,standard ,web,Express ,Workgroup , 64- bit Edition .

The following table lists the Sqlservr.exe version number.

Release	Sqlservr.exe
RTM	2007.100.1600.0
SQL Server 2008 Service Pack 1	2007.100.2531.0