There are a lot of tools in SQL Server 2005 that will help you with indexes, from enhanced plan diagrams to the Database Tuning Advisor. But I was scouting around this morning for a script that would find places where I had indexes that included duplicate columns - that is unecessary and could potentially confuse the Query Optimizer into choosing a less than effective index or at least make it compare the overlaps. Well, the Microsoft SQL ISV Program Management Team has a blog entry with a function they made to do just that in SQL Server 2005:

http://blogs.msdn.com/mssqlisv/archive/2007/06/29/detecting-overlapping-indexes-in-sql-server-2005.aspx