As you might have seen, you can plug in your own reports in SQL Server Management Studio as of sp2. The MS tool team has made such a package, the SQL Server 2005 Performance Dashboard Reports. Check it out at::
http://www.microsoft.com/downloads/details.aspx?FamilyId=1D3A4A0D-7E0C-4730-8204-E419218C1EFC&displaylang=en