One of the new adapters we’ve added in Microsoft BizTalk Server 2010 R2 is the WCF-WebHttp Adapter. This adapter is designed to make it easy for users to consume REST services as well as expose REST endpoints using BizTalk. The Adapter allows you to easily define URI parameters and map them to BizTalk Context Properties, accept multiple HTTP Verbs (Methods), specify (and inspect) HTTP Headers as well as the HTTP Status Code and Status Description. The adapter aims to provide the framework-ish pieces into which you can hook in your extensibility pieces (BizTalk Pipeline Components, or WCF Behaviors) that make it easy to interact with various REST services you may have.
Please let us know if you have any suggestions / feature requests for adding more platform-level features in the adapter. When adding your comments, if you leave behind a way to contact you, we can get in touch with you when we begin to explore and think about your suggestion.