External List

Good Morning--
The Normal sharepoint but it gets data from Line of Business Object..confusing right?
This is new feature of Sps2010 where the sharepoint list can import all data from any external system using 'Business Connectivity System' [BDC in MOSS]
The cool feature is after getting all data from external system, the developer can play with it like normal sharepoint list, can add column, data into column etc.

Excel Services and soap

Excel Services and Soap call.

javascript enabled web services can be used to get client side activites in Excel services.
Below is the code snippet for getRangeA1 -

request = new ActiveXObject("Microsoft.XMLHTTP");
var url = "http://localhost/_vti_bin/excelservice.asmx";
var envelope = "<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">"+
"<soap:Body>"+
"<getcella1 "+
"xmlns=\'http://schemas.microsoft.com/office/excel/server/webservices\'>"+
"<sessionid>"+ EwaGetSessionId('WebPartWPQ3') +"</sessionId>"+
"<sheetname>"+"Sheet1" +"</sheetName>"+
"<rangename>"+"B3"+"</rangeName>"+
"</GetCellA1></soap:Body></soap:Envelope>";

alert(envelope);
request.open("Post",url,false);
request.setRequestHeader("Content-Type","text/xml");
request.send(envelope);
alert(request.statusText);