Well, you've said it yourself: SpreadSheet::ParseExcel. On Windows and provided you have Excel on your system, you can also use Win32::OLE, but IMO it's harder. The former is platform-independent and is standalone — no need for Excel.

A quick look on CPAN showed me there's Spreadsheet::BasicRead too, but that is built on top of SpreadSheet::ParseExcel. You can see for yourself if you like it.