This will use GPT partitions and GRUB2 on a BIOS enabled PC (see Wiki for EFI). The Installation Guide can be found at /root/install.txt.
Get 2012.08.04 image or later from http://www.archlinux.org/download. Following tutorial requires at least 2011.07.15 image.
dd if=/dev/zero of=/dev/sdx bs=1k count=1