The new XenApp template for XenServer has generated a great deal of interest. There have been a several posts about XenApp on XenServer on the Citrix Blog (read Dan Feller's posts here, here, here and here). You can listen to an interview with Dan about this topic as part of the Citrix Delivery Center podcast here. Recently Laura Whalen in our Solutions Marketing team put together an excellent slide presentation that covers the reasons why you would want to virtualize XenApp on XenServer.