With DataSnap in Delphi 2010, you can develop DataSnap clients and server that communicate over HTTP. One way to implement the server is as an ISAPI dll. I've been given permission to show this feature pre-release. See http://www.embarcadero.com/rad-studio-2010 for for more information about the upcoming release.
Click these links to skip ahead Configure IIS, Connect with Data Explorer, Ancestors and DataModules, ISAPI debugging
In the File/New… dialog, double click “DataSnap WebBroker...