Red Hat's own documentation can be found here:
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Virtua...

Set up bridging on server:

• http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Virtua...
• Follow suggestion: Instead of turning off NetworkManager, add "NM_CONTROLLED=no" to the ifcfg-* scripts used in the examples.

Please be aware that I was not 100% successful using this method:
Note that you cannot install Fedora 10 on RHEL/CentOS 5.2 using virt-install since the image structure has changed. You will need to use the new virt-install in 5.3

• Prepare LVM with:
  lvcreate -L 5G -n vm_fred vg
  lvcreate -L 1G -n vm_fred_swp vg
  /sbin/mkswap /dev/vg/vm_fred_swp
• for installation under RHEL/CentOS (note that 32 bit domU's can only run under 32 bit dom0's)
• Set up the install location with:
  

My process is to create the VM under Ubuntu/Hardy and then move it across

Resources

There is an article at: http://www.howtoforge.com/ubuntu-8.04-server-install-xen-from-ubuntu-rep... which is the basis, but *don't do the wget and dpkg steps* since the patches are now in hardy

1. /usr/sbin/lvcreate -L 10G -n vm_mymachine VolGroup00 #first create a logical volume for the machine
2. dd if=/dev/scd0 of=/var/lib/xen/images/media/winxp.iso #create an ISO image of the XP cd-rom
3. run the graphical virtual machine manager
4. make the source of the installation: /var/lib/xen/images/media/winxp.iso
5. format partition to FAT since then it is editable from within CentOS host
6. the first reboot will fail. Before restarting, do the following:

#create a snapshot of the LV drive
/usr/sbin/lvcreate -L5G -s -n vm_test_snap /dev/VolGroup00/vm_test
#turn the snapshop into a file image
dd if=/dev/VolGroup00/vm_test_snap | gzip -9 >/backup/vm_test.dd.gz
#remove the snapshot

My process is to create the VM under Ubuntu/Gutsy and then move it across

Resources

There is an article at: http://www.howtoforge.com/ubuntu-7.10-server-install-xen-from-ubuntu-rep... which unfortunately has a number of flaws. For more information, see:

I would recommend not using LVM within a VM because it makes it harder to back up the files within the VM

My default Zimbra VM install uses LVM within its own virtual machine. This makes it harder to get at the data from outside the VM, and so complicates backup. The following steps need to be taken

Here is a list of useful documentation

• Official Red Hat 5.1 manual: http://www.redhat.com/docs/manuals/enterprise/RHEL-5-manual/en-US/RHEL51...
• CentOS version: http://www.centos.org/docs/5/html/Virtualization-en-US/
• Xen Wiki: http://wiki.xensource.com/xenwiki/XenDocs
• A very useful set of notes on messing around wtih VM's and LVM's: http://www.redhat.com/archives/fedora-xen/2006-November/msg00257.html