This file was pre-historic, so still looked correct.

Get the Pobox-x.xx.tar.gz file - use binary mode if FTP'ing.
  where x.xx is version number

Unpack it e.g.
                                  
gunzip -c Pobox-x.xx.tar.gz | tar xf - 
  or
tar zxf Pobox-x.xx.tar.gz

cd to the directory distribution unpacks to.

perl Makefile.PL
make 
make test (optional, but recomended)
make install
