I have posted ExcelLite an open source C# library for Silverlight applications for manipulating MS excel without COM interaction or OLEDB driver.You can manipulate MS Excel (97-2003) files totally in silverlight client as this library using Binary excel format to read and write data.
So you don’t need to force your client to install Silverlight application “out of browser” as well as no COM interaction required with office DDLS.
Download ExcelLite from codeplex.
Following is the series of posts that describing various features of the library with sample applications.
Exports Silverlight data to MS excel
Example code and description for writing excel files with ExcelLite
Imports excel data in Silverlight application.
Example dode and description for reading excel files into Silverlight with ExcelLite
Export Silverlight image to excel file
Example , how to export silverlight image to an excel file with ExcelLite