TAGSETS.EXCELXP generates MIcrosoft Spreadsheet Markup Language XML tags that describe the worksheet. Sadly, Microsoft introduced this XML description of the spreadsheet in Office 2002/2003. So even if you have SAS 9 and CAN create SpreadsheetML XML with SAS, you can only open it with Office 2002/2003 or higher.
If you use ODS HTML, you can create multiple HTML files; and then, there is one method for linking those separate HTML files together -- again, using a Microsoft form of XML and HTML for describing the relationship of the files. Basically, for this to work, you would use SAS to create the multiple HTML files. But, unless you know a lot about coding SAS data step programs, building the HTML and XML to link the files together is a manual process. (That method is described in this presentation: http://support.sas.com/rnd/base/ods/excel/multisheet_excel_post.ppt )
This is great, but for some reason, I get the error message: ERROR: Insufficient authorization to access c:\your workbook.xls, although it works if I put the file on our server and change the file name accordingly...