The previous version of Aspose.Cells allowed you to convert Excel XLS to HTML file and converting worksheet to image. However the latest version supports to read and write XLTM and XLMX files. Many new features like: Exporting Pivot Table to Excel 2007 file and adding pivot calculated item to pivot table in 97-2003 XLS file are also supported now. Aspose.Cells is a .NET component for spreadsheet reporting without using Microsoft Excel. It supports robust formula calculation engine, pivot tables, VBA, workbook encryption, named ranges, spreadsheet formatting, drawing objects like images, OLE objects and importing or creating charts. You can also create Excel file using designer spreadsheet, smart marker or API and apply formulae and functions. It supports CSV, SpreadsheetML, PDF and all file formats from Excel 97 to Excel 2007.

Read more: http://www.aspose.com/community/blogs/aspose.cells/archive/2008/12/12/aspose-cells-for-net-v4-6-0-released.aspx