I just noticed that there is an update to R on the CRAN website
This binary distribution of R and the GUI supports 64-bit Intel based Macs on Mac OS X 10.6 (Leopard) or higher. Since R 3.0.0 the binary is a single-arch build and contains only the x86_64 (64-bit Intel) architecture. PowerPC Macs and 32-bit Macs are only supported by building from sources or by older binary R versions. The default package type is "mac.binary" and the binary repository layout has changed accordingly.