Excel's XML features

SpreadsheetML A slightly enriched version of the XML available in prior versions of Excel, SpreadsheetML is very convenient for extracting information that had previously been locked up in spreadsheets. SpreadsheetML contains most of the Excel spreadsheet's content, omitting Visual Basic for Applications and charts.
Custom XML Excel lets you create lists in spreadsheets which are filled from XML documents conforming to a given schema. (It can even import files without a schema.) These lists can then be used as regular spreadsheet content, and the data updated whenever appropriate.