I mentioned in a previous post that I would post again when I updated my screencast series on Workflow Foundation. Today I submitted the third (and probably final) screencast in this series titled Service Enabling Workflows.
Many don't realize that the Workflow Foundation provides an interface-driven service layer to the workflows and activities that run within it. This service layer enables SOA architectures within workflows and allows activities to communicate with the host, the operating environment or even potentially other systems.
If you want your workflows to communicate with their host, or you'd like to build environment agnostic activities this 11 minute how-to can point you in the right direction.
Please note that this how-to is not about consuming or exposing WCF service in a workflow. If you're more info on that topic, please see this 3-part series on Channel 9.