Connect the API of one website with an Excel worksheet

I want an application that connects the API of one website with an Excel worksheet. It must be compatible with Excel 2002. The API is based on XML, SOAP and WSDL. The hired coder will receive extensive information about classes, calls etc. (1) Data published by the API should be written into Excel cells. As the data are changing all the time this has to be repeated automatically as often as the request limit of the API allows it. (2) When certain Excel cells are changed a message should be sent to the API automatically. (3) I want a short description how to edit the code if necessary. Other things like appearance and used programming language are secondary as long as the above is fulfilled.