I spent a couple of hours yesterday with a couple of good folks from WRQ. We talked about Verastream, a product of theirs that specializes in exposing Host-based services. Assume for a second that you have a mainframe, or a OpenVMS system, or an AS/400, etc. Some type of legacy back-end system that has an application that contains business logic that is critical to your company, but the only way to get access to those transactions is via a 3270 terminal interface. Verastream can be used to provide alternate interfaces to those applications, and can provide the services that are contained within your host apps and surface them in ways that your .Net, SOAP, or COM-based apps can leverage. Yes, Verastream will take a 3270 terminal based app and wrap it up into a SOAP web service. Very cool technology.
WRQ has an adapter for BizTalk Server 2004 for the Verastream product, so all of your BizTalk applications can now leverage functionality contained on your host. This is an intriguing product and I think it will be a good way for SOA-based architectures to start to take root even in organizations with host-based systems.