I have been searching for the right alternative for managing my Xen VM’s and hosts. Its a pain to boot a Windows VM just for accessing XenCenter. You can download OpenXenManager from http://sourceforge.net/projects/openxenmanager/ or Install it on your Ubuntu machine using the following command:
#sudo apt-get install openxenmanager
PS: Running it from the source from SF.net link didn’t work for me on Ubuntu 12.04 but found it working after installing via apt-get.
Once installed, its very similar to working with the windows version of Citrix Xen Center.
Hope you too find it useful.