I have been asked for more information on migrating log shipping from SQL 2000 to SQL 2005.  There are several white papers covering this in some detail.  There is no direct upgrade as the Database Maintenance Plan Wizard is not used in SQL server 2005,  so during an upgrade log shipping stops functioning.  There are two methods suggested for migration in a white paper on MSDN

For those new to log shipping there is an excellent article covering all the features of log shipping here

If it is high availability you require then there is a new SQL course available.  2788 Designing High Availability Database Solutions Using Microsoft SQL Server 2005, this is a 3 day instructor led course.  Module 4 covers designing and planning a log shipping solution.