[R] help with updating to R2.7

[ravi]

Hi,
From R 2.6, I would like to update to R2.7. I would like to have some tips on the recommended method of installing the latest versions of an entire list of packages in R2.7 - i.e. all the packages that I have presently installed in R2.6.
I am hoping that there is an easier method than fetching the packages individually as I did, to begin with, for R2.6.
Additionally, I would like to install R2.7 on another pc which is not connected to the internet. I have previously installed R2.6 on it by fetching the zip files from another pc and installed them from the local zip files. I would like to know if there is a method of transferring an entire installation (base+selected packages) from one pc to another. Will there be a special problem if the first is a win vista pc and the 2nd has win 2000?
One problem that I have in continuing to use R2.6 is in getting compatible versions of a new package that happens to attract my interest. For example, I was interested in getting the arm package for R2.6.1. I could not find the package in the "R Binaries" list on CRAN webpage. In the packages list, I did find old versions in the "arm archive". However, the files were in ".....tar.gz" format. How does one install from this format? It does not appear to be as straightforward as in installing from the zip format files.Recently, I had the same problem in installing a compatible version of the "norm" package also. I am interested to know how I can tackle these problems.
I will appreciate all the help that I can get.
Thanks,
Ravi