GRaF is an R package for fitting species distribution models using Gaussian random fields. There is a version of GRaF on CRAN, but this is the development version so will get the updates first.
To install this development version of GRaF you can use the install_github function in the devtools package, like this:
# install devtools if you haven't already
# install.packages('devtools')
# load the package
library(devtools)
# install GRaF from github (the version from goldingn's repo at least)
install_github('GRaF', 'goldingn')
# and load it
library(GRaF)
If you find a bug in the code or have suggestions for improvements, please let me know via the issues reporting system (button on the right of this page).
I presented a tutorial to GRaF at the INTECOL2013 conference, as well as a reasearch talk on the approach. You can find links to these and a number of other related things over at the repo I set up for the conference.