Another Excel 2007 whitepaper is available. According to the description, “This paper has been developed to aid IT professionals in the process of migrating to Microsoft Office Excel 2007. Here you will find descriptions of the primary functional differences and how those variances might affect workbooks. This paper also explains some of the more common issues that may arise during migration and offers solutions where applicable. Additional resources are provided to help diagnose any issues that are not described in this paper.”
You can find the paper here.