The GNU Guile-RPC web page is located at http://www.gnu.org/software/guile-rpc/. You can obtain copy of GNU Guile-RPC from ftp://alpha.gnu.org/gnu/guile-rpc/.
In order to use GNU Guile-RPC, all that is needed is GNU Guile 1.8 along with the R6RS library package for Guile 1.8, known as Guile-R6RS-Libs1.
Before version 1.8.3, Guile 1.8 did not contain an implementation of SRFI-35. Thus, if you are using one of these versions of Guile, you need to install Guile-Lib, which contains the relevant module.
GNU Guile-RPC comes with a compiler for the XDR/RPC interface description language (see Invoking grpc-compile). To use that, Guile-Lib version 0.1.7 or later is needed2.