See http://www.berezniker.com/display/SQL/Retrieving+SQL+Server+Edition%2C+Version+and+Service+Pack+Info

>Sorry about my English!
>I have 2 instances of SQL running at my server.
>I believe that they are not from same version.
>After connecting to them how can I know which
>version they are and which Service Pack have they
>been upgraded? Using SQL commands? Which ones?
>By the way, taking in attention performance (relative
>to RAM and processor) which option is the best:
>a) Have 4 databases in 1 instance of SQL;
>b) Have 2 databases at 2 instances of SQL.