Some clients I have worked with have taken hold of Excel Services and are asking for clarification on requirements for publishing Excel Services Web based workbooks. Per Microsoft documentation, you need Microsoft Office Ultimate 2007, Office Professional Plus 2007, Office Enterprise 2007 and obviously, Office Excel 2007. Since you get Office Excel 2007 throughout the entire Office 2007 product line (see table below) there's some clarification needed here: In order to get the enhanced UI in Excel using the Publish menu and subsequent 'Save As' options to hide or expose workbook data, you will need one of the prior mentioned Office flavors.

Excel Services Publish options between Office versions.

Options available within Office 2007 Plus, Enterprise and Ultimate.

So, even if you have Office Home, Office Student, Standard and Small Business or Professional (Not Plus, Ultimate or Enterprise) you can still publish through 'Save As' by entering the full path to the Document Library http://server/DocumentLibrary/ Of course all MOSS farm server Excel Services settings are still required for web browsing to the published workbooks. Click here for the Channel 9 video download which outlines some of those requirements. Yes, you will lose out on a lot of Excel Services options as shown in the same video but you can still publish the 2007 versions (XLSX) of your workbooks straight into an Enterprise version of MOSS and view through clicking on the workbook in the doc lib or the Excel Web Access Web Part.

See Also: http://office.microsoft.com/en-us/products/fx100487411033.aspx