Although I wrote this app, it is published through the Citrix CDN site. At the Citrix CDN page you will find a link for the binary msi distribution or source code.
Update: 10/2013 Citrix has reorganized their site. This version appears to no longer be available for download.
Also see these updated versions:
XenApp Publishing Extensions 3.0 for XenApp 5.5 and above
PublishFromAppV for XenApp 6.5