SQL Server administration tools

SQL Server Management Studio

SQL Server Management Studio is Microsoft's own application for configuring, managing, and administering Microsoft SQL Server. 

A free Express version is available. 

RedGate SQL Toolbelt

The RedGate SQL Toolbelt contains the following products:

SQL Compare
Compares and syncs SQL Server database schemas

SQL Data Compare
Compares and syncs SQL Server database contents

SQL Source Control
Connect your existing source control system to SQL Server

SQL Prompt
Write, edit, and explore SQL effortlessly

SQL Doc
Document SQL Server databases

SQL Data Generator
Test data generator for SQL Server databases

SQL Dependency Tracker
Visualizes SQL Server object dependencies

SQL Packager
Packages a database for deployment or update

SQL Comparison SDK
Automates comparison and synchronization tasks

SQL Search
Search within SQL Server database schemas

SQL Multi Script
Deploy multiple scripts to multiple servers with just one click.

Data Cleanser Beta
Free SSIS component for cleansing data

SQL Connect (Preview)
Source control add-in to Visual Studio

SQL Test (Preview)
Unit testing plug-in for SQL Server Management Studio