Gérald,
The original poster was asking about sending email from an application, and I assume it is a desktop application. Claude suggested CDONTS, and my point is that it is not really a valid option for sending email from an end-user application. I suppose CDO could be considered instead...
From MS KB:
Applications written using CDO for NTS must run on the server computer. Unlike CDO 1.2 for Exchange, applications cannot be written to access remote servers or to develop client applications. All of the configuration information such as SMTP server is gathered from the host computer. This configuration cannot be modified using the library. Since one of the three programs is required to use CDO for NTS, there is no standalone setup program.The entire article:
http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q177850>
>Windows 2000 server come with CDO installed as system component (not only with IIS).
>see
http://msdn.microsoft.com/library/en-us/dncdsys/html/cdo_roadmap.asp
Steve Gibson