QEMU-Buch / QEMU-Book - a quite versatile book on qemu, provided in German and English (partly as a google translation), its describing e.g. lots of guests and hosts
Ubuntu Development Ports - details on qemu-<arch> usage, chroot set up, system emulation and cross compilation
Compiling with qemu-user chroot - details on tuning binfmt_misc with magic patterns for making alien binaries run from the shell with silent invocation of QEMU