A: When SQL Server is installed, there's an option in the management tools to install the SQL Server Management Studio. Management Studio is a great way to view databases, security, replication, and pretty much all aspects of SQL Server, including running SQL statements. The tool is used by both administrators and developers.
It's also possible to download SQL Server 2008 Management Studio Express from Microsoft for use managing and developing against SQL Server. Both 32-bit and 64-bit versions are available. Once you've downloaded the installation file, just make sure you check the option for Management Tools - Basic and then proceed with the installation.
Note that the Express version doesn't offer the same functionality as the full SQL Server Management Studio and it can't manage Analysis Services, Integration Services, or Reporting Services. Nor can its Object Explorer connect to any service other than Database Engine instances. There are a few other differences, detailed on this Microsoft site, but think of the Express edition as great for managing Database Engine instances and the full edition for managing everything SQL Server related.