You can just connect to Excel *AS IF* the ".xls" file is a database and then read the contents of any sheet (or even any range of cells, etc.) as if it were a DB table.
So then you can just use all of ASP.NET's DB-related controls. Such as DataGrid and the like.
For how to make the connection look here:
http://www.carlprothman.net/Default....anagedProvider
and here:
http://www.carlprothman.net/Default....orMicrosoftJet
(scroll down to "You can also open an Excel Spreadsheet using the JET OLE DB Provider")