Don't worry! It's only stuff...

Netinstall CD
http://cdimage.debian.org/debian-cd/current/amd64/iso-cd/
http://ftp.debian.org/debian/dists/squeeze/main/installer-amd64/current/images/netboot/ - squeeze netinstall cd

Net install from PXE
wget http://ftp.debian.org/debian/dists/squeeze/main/installer-amd64/current/images/netboot/netboot.tar.gz -O /tmp/netboot.tar.gz
#wget http://ftp.debian.org/debian/dists/wheezy/main/installer-amd64/current/images/netboot/netboot.tar.gz -O /tmp/netboot.tar.gz
tar xzf /tmp/netboot.tar.gz -C /tmp/
cp -a /tmp/debian-installer/ /var/lib/tftpboot/
echo "LABEL linux" > /var/lib/tftpboot/pxelinux.cfg/debian-installer.cfg
echo "MENU LABEL debian-installer" >> /var/lib/tftpboot/pxelinux.cfg/debian-installer.cfg
cat /tmp/debian-installer/amd64/boot-screens/txt.cfg | tail -2 >> /var/lib/tftpboot/pxelinux.cfg/debian-installer.cfg
echo "MENU INCLUDE pxelinux.cfg/debian-installer.cfg" >> /var/lib/tftpboot/pxelinux.cfg/default

Net install Debian (boot installer from HDD)
# get boot files
mkdir /boot/debian-installer/
wget http://ftp.debian.org/debian/dists/squeeze/main/installer-amd64/current/images/netboot/debian-installer/amd64/initrd.gz -O /boot/debian-installer/initrd.gz
wget http://ftp.debian.org/debian/dists/squeeze/main/installer-amd64/current/images/netboot/debian-installer/amd64/linux -O /boot/debian-installer/linux

# edit grub config
vi /boot/grub/grub.cfg
menuentry 'Debian Installer' {
linux /boot/debian-installer/linux
initrd /boot/debian-installer/initrd.gz
}

Preseed
http://d-i.alioth.debian.org/manual/en.i386/apb.html