Indigo Beta 2 will support the use of HTTP operations such as POST, PUT, and DELETE for interacting with services. The use of HTTP operations instead of more formal XML based abstractions is a fundamental principle of REST (Representational State Transfer).

From Wikipedia:
While REST originally referred to a collection of architectural principles (described below), people now often use the term in a looser sense to describe any simple web-based interface that uses XML and HTTP without the extra abstractions of MEP-based approaches like the web services SOAP protocol. Strictly speaking, it is possible (though not common) to design web service systems in accordance with Fielding's REST architectual style, and it is possible to design simple XML+HTTP interfaces in accordance with the RPC style, so these two different uses of REST cause some confusion in technical discussions.
The support for REST also requires the ability to send and recieve XML that is not based on SOAP, which is a current default limitation in Indigo but can apparently be turned off.

Via The ServerSide.Net