Check out this new white paper which details how to configure Database Mirroring in SQL 2005 for SharePoint Server and WSS 3.0. (Includes T-SQL Commands)

Using Database Mirroring with Office SharePoint Server and Windows SharePoint Services (http://go.microsoft.com/fwlink/?LinkId=83725&clcid=0×409)

Table of Contents
Introduction to Database Mirroring

• Database Mirroring Modes
• Security Associated with Database Mirroring

How to Set Up Database Mirroring with SharePoint Products and Technologies

• Prerequisites
• Recommended Topologies
• Recommend Database Limits
• Performance and Scale
• Setup Steps
• Database Mirroring with Certifcates and Full Recovery
• Setting  up a Witness Server

Recovering from a Failure

• Types of Failover
• Automatic Failover
• Manual Failover
• Forced Failover (possible data loss)
• Notifying SharePoint Products and Technologies when a Failover Occurs
• Configuration Database and Administration Content Database
• Content Database
• Search Database
• Shared Service Provider Database (Office SharePoint Server only)

Source: Microsoft SharePoint Products and Technologies Team Blog