Please note that RSAGA development has moved to https://github.com/r-spatial/RSAGA.
RSAGA Package Code and Vignette
Currently updated to RSAGA 0.94-5, available on CRAN
Supports SAGA GIS 2.0.4 - 2.2.3
Provides access to geocomputing and terrain analysis functions of the geographical information system (GIS) 'SAGA' (System for Automated Geoscientific Analyses) from within R by running the command line version of SAGA. This package furthermore provides several R functions for handling ASCII grids, including a flexible framework for applying local functions (including predict methods of fitted models) and focal functions to multiple grids. SAGA GIS is available under GPLv2 / LGPLv2 licence from http://sourceforge.net/projects/saga-gis/.