One more thing: How can I pass parameters to my .exe app from ASP.NET?
There's built-in support for mail in ASP.NET. Take a look at the System.Web.Mail namespace. You can easily send mails from there.
As for passing parameters to a .exe, you should use the ProcessStartInfo and Process classes in the System.Diagnostics namespace:
ProcessStartInfo i = new ProcessStartInfo("myexe.exe", "-arg1 -arg1 -others");
Process p = new Process();
p.StartInfo = i;
p.Start();
This was first published in June 2003