Once the system is booted into the Xen kernel, check to verify the kernel and that Xen is running:
The above output should show that the xen kernel is loaded and that Domain-0 (the host operating system) is running.
Note that for the default setup, networking for guest OS's is bridged. This means that they will get an IP address on the same network as your host, thus, if you have a DHCP server providing addresses, you will need to ensure that it is configured to give addresses to your guests. You can change to another networking type by editing /etc/xen/xend-config.sxp