Here is how to identify the version. Connect to the database server in question using Query Analyzer or SQL Server Management Studio and run the following SQL.
The above query on SQL 2005 returned 9.00.3042.00 and your result may vary depending on the Service Pack level. Generally speaking, SQL Server 2000 is version 8.x, 2005 is version 9.x and 2008 is version 10.x.
Hope this helps.