This week's book giveaway is in the Other Open Source APIs forum. We're giving away four copies of Storm Applied and have Sean Allen, Peter Pathirana & Matthew Jankowski on-line! See this thread for details.
I don't really understand the question, since RPC is a style you can use to do webservices. OFten webservices (the SOAP ones) are divided into two styles. RPC Style webservices and document style webservices. In the early days of webservices RPC was most often used, but this caused all kinds of performance and interoperability issues. Microsoft was one of the first to start with document/literal way of webservices. This provided an easy way to map webservices to server implementations and also allowed for easy interoperability.