[poli-smen]

Через TXMLDocument можно так:

Код:

uses
  XMLDoc, XMLIntf;
.....
procedure TForm1.Button1Click(Sender: TObject);
var
  xml: TXMLDocument;
  Node: IXMLNode;
begin
  xml := TXMLDocument.Create(Application);
  try
    xml.LoadFromFile('careerSavegame.xml');
    Node := xml.ChildNodes.FindNode('careerSavegame');
    if Assigned(Node) then
    begin
      Node.Attributes['money'] := 1000000;
      xml.SaveToFile('careerSavegame.xml');
    end;
  finally
    xml.Free;
  end;
end;