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