Execute the following commands on a RedHat/Fedora/Centos box to update vim to support asterisk syntax highlighting:

[ -d /usr/share/vim/vim63/syntax/ ] && cd /usr/share/vim/vim63/syntax/
[ -d /usr/share/vim/vim70/syntax/ ] && cd /usr/share/vim/vim70/syntax/
wget http://files.bluecrow.net/asterisk/vim/asterisk.vim
wget http://files.bluecrow.net/asterisk/vim/asterisk_voicemail.vim

cd
wget http://files.bluecrow.net/asterisk/vim/vim-asterisk-patch.txt
[ -d /usr/share/vim/vim63/syntax/ ] && cat vim-asterisk-patch.txt >> /usr/share/vim/vim63/filetype.vim
[ -d /usr/share/vim/vim70/syntax/ ] && cat vim-asterisk-patch.txt >> /usr/share/vim/vim70/filetype.vim
rm -f vim-asterisk-patch.txt