I\'ve been searching several days for a descent answer on how to acquire the list of installed applications on a device running iOS > 5.0 (com.apple.mobile.installation.pl
You can take a look into iTUnes Search API
http://www.apple.com/itunes/affiliates/resources/documentation/itunes-store-web-service-search-api.html
Theoretically you could but that is accessing private ivar which is strictly prohibited by Apple.
I don't know if Apple will ever authorised it. Honestly I don't think so. But for technical fun, if you want to do that, check how Airwatch or other MDM solution work, they can show all the apps installed.
Have fun !