The latest version of the package is available from bioconductor: http://bioconductor.org/packages/release/bioc/html/exomePeak.html
With the latest version of R, you may install it with the following command:
source("http://bioconductor.org/biocLite.R")
biocLite("exomePeak")
If you are using an old version of R, you may have to download and install it manually.