Which component of .NET Framework can be used to build RESTful services?

In the .NET Framework 3.5, WCF added support for REST-style communications.

Developers can specify URL Templates on Operation Contracts, to allow methods to be invoked when requests on specific URLs are received.

Parameters from the URLs can be automatically extracted and passed to the method.

JSON and plain-old-XML data serialization is supported, as well as alternative mechanisms for binary return types (such as JPG).