Over the weekend I tried to follow the instructions at:
http://www.netbsd.org/ports/xen/howto.html
To install NetBSD, install Xen 3 and get a NetBSD DOM0 up and going.

The process for some reason was not as straight forward as the link 
above lets on the believe.
As I went to the whole process several times I made notes of the steps:

Download:
ftp://ftp.netbsd.org/pub/NetBSD-daily/HEAD/200801140002Z/amd64/installation/cdrom/boot.iso
and perform NetBSD 5.x install.
Base path for binary down load is: pub/NetBSD-daily/HEAD/200801140002Z
Make sure to create a / (root) file system <= 512Mb as grub does not 
seem to understand anything larger.
/ 512Mb
/swap: 1024Mb?
/tmp: -> MFS
/var: 2028Mb?
/usr: rest
To do this, hard-set the size of the / root file system in disklabel!

(I only created a 32 Gb partition for NetBSD on a 400 GB drive)

After install, reboot:

login as root
# Get pkgsrc:
cd /usr
cvs -d :pserver:anoncvs@anoncvs.netbsd.org:/cvsroot login
passwd: anoncvs
cvs -d :pserver:anoncvs@anoncvs.netbsd.org:/cvsroot checkout 
-rpkgsrc-2007Q4 pkgsrc

# Install Xen Tools 3
cd /usr/pkgsrc/sysutils/xentools3
make install

# Install Xen Kernel 3
cd /usr/pkgsrc/sysutils/xenkernel3
make install
cp /usr/pkg/xen3-kernel/xen.gz /

# Install Xen Tools 3 HVM
cd /usr/pkgsrc/sysutils/xentools3-hvm
make install

# Install NetBSD 3.0 32 bits compatibility for Grub as that according to 
the link does NOT build on amd64!
cd /usr/pkgsrc/emulators/netbsd32_compat30
make install

# Install DOM0 NetBSD (HEAD) kernel!
Make sure to grab the XEN3_DOM0 kernel from ftp.netbsd.org:
ftp://ftp.netbsd.org/pub/NetBSD-daily/HEAD/200801140002Z/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
Unzip it and place it in the root (/).

# Install Grub
pkg_add -f 
http://ftp.netbsd.org/pub/pkgsrc/packages/NetBSD/i386/3.1_2007Q4/All/grub-0.97nb8.tgz

# grub-install /dev/wd0d

Create /grub/menu.lst as: http://www.netbsd.org/ports/xen/howto.html
Make sure to update menu.lst so it refers to the proper XEN3_DOM0 kernel!!!

Run grub as: http://www.netbsd.org/ports/xen/howto.html
exit

Reboot and startup with Xen...

The system indeed seem to start up, however...
During boot the system gives this:
Searching for RAID components...
boot device: <unknown>
root device: [Here I enter: wd0a]
dump device (default wd0k): [Here I just enter]
file system (default generic): [Here I enter: ffs]
init path (default /sbin/init): [Here I just enter]

Than the system continues to boot and shows a Login prompt.
However, after login the terminal settings seems to be bogus:
<Backspace> and other keys that make life easy for command line editing 
do not seem to work well.

I do not seem to be able to launch X... (startx)

after xend and xenbackendd have been started I see one LISTEN on 8002 I 
thought there would have been a VNC Server started?

Any help would be welcome.

Thanks!
Jan