SharePoint 2007 Database Maintenance

Here are a series of useful TechNet articles on  Database maintenance for Microsoft Office SharePoint Server 2007 MOSS

Add, split, and merge content databases

Database maintenance (Office SharePoint Server 2007)
Database maintenance for Office SharePoint Server 2007 (white paper)
Planning and Monitoring SQL Server Storage for Office SharePoint Server: Performance Recommendations and Best Practices (white paper)
Move content databases (Office SharePoint Server 2007)
Move all databases (Office SharePoint Server 2007)