Microsoft SQL Server 2008

 Get Started with SQL Server 2008 CTP here

Microsoft SQL Server 2005

Administration Tools

Microsoft Tools

• Best Practices Analyzer
• Database Tuning Advisor
• Health Checker
• Performance Dashboard
• Upgrade Advisor

FREE! Download SQL Server Express Here

IBM DB2 Universal Database

FREE! Download DB2 Express-C Here

MySQL

Administration Tools

• phpMyAdmin

FREE! Download MySQL Here