Building bochs

The required libraries must be installed somewhere,
I let MacPorts build and install bochs to get
the libraries installed into /opt/local

Download bochs from svn in SRC, configure and make:

cd $SRC

CFLAGS="-I/opt/local/include -arch i386" \
CXXFLAGS="-L/opt/local/lib -arch i386" \
LDFLAGS="-L/opt/local/lib -arch i386" \
./configure \
--exec-prefix=/opt/local \
--bindir=/opt/local/bin \
--mandir=/opt/local/share/man \
--enable-all-optimizations \
--enable-cdrom \
--with-vbe \
--without-x \
--with-sdl

make -j8

Make a HD image

./bximage -q -hd -mode=sparse -size=1024 $SRC/c.img

./bochs

Configure hard disks, cdrom, bios files and boot order to boot from cdrom.
Use these files

$SRC/c.img
~/Downloads/ubuntu-10.04.2-server-i386.iso

$SRC/bios/BIOS-bochs-latest
$SRC/bios/VGABIOS-lgpl-latest


To make it faster, change the default ips from 50000000 to 4000000
cpu: count=1, ips=4000000, ....