Using pkg_add on alternative host

I am using pkg_add to add packages to a FreeBSD 7.1 install. This command is fetching from ftp.freebsd.org, which is known to be slow from my geographical location. Can I set a variable so that the package is fetched from a host closer to the machine (ftp.xx.freebsd.org)?

# export PACKAGEROOT=ftp://ftp3.FreeBSD.org
# pkg_add -v -r vim

hi,
look in the man

Thank you for your response. I have since added to my post installation script:

# set package source location
export PACKAGEROOT=ftp://ftp.xx.FreeBSD.org

where 'xx' is the top level domain of the country of choice.