SQL Server: What service pack am I on?

Anyone remember the SQL Slammer virus? It turns out that it attacked SQL Server databases (and SQL Server DBA's) that were not protected by the latest Service Pack. I sit around and scare myself by asking myself questions like, what service pack am I on?

Here is a simple query to tell you what service pack you are on and some other interesting information about your SQL Server instance:

select serverproperty ('servername') [Server Name],
       serverproperty ('productversion') [Product Version],
       serverproperty ('productlevel') [Product Level],
       serverproperty ('edition') Edition,
       serverproperty ('licensetype') [License Type],
       serverproperty ('numlicenses') [# Licenses]

Of course you have to connect to the server you are interested in before running this query. The Service Pack level will be in the "Product Level" column.