I just tried Rphylip in R on Mac OS X. It appears to work fine, although the internal function findPath will not - so the full path to the PHYLIP executables needs to be supplied by the user. However I also discovered that is is very important that the installation protocol for Mac OS X described here on the PHYLIP installation page needs to be followed or else it will not work. Since this protocol involves commands that can be executed from the terminal, I may write a simple R script for Rphylip that will run these commands for the user to make it even easier.
More soon.