I recently downloaded and read ExcelAndTheWorldWideWeb by Eduardo N. Sanchez, available in the MrExcel bookstore. It's an informative read but leaves out information on Excel's WEBSERVICE() function which, with a little imagination and a bit of PHP scripting, can be used to communicate with a wide variety of REST APIs and, more importantly, SQL databases. I apologize in advance if this approach seems a little out-of-left-field, it just works really well and I thought Excel enthusiasts would get a kick out of it's relative simplicity.
You can view a web-enabled Excel spreadsheet example, complete with PHP scripts, at Web-enabled Spreadsheets
You can view a web-enabled Excel spreadsheet example, complete with PHP scripts, at Web-enabled Spreadsheets