This YouTube app is a full backend interface enabling you to search and save any YouTube video (and also channels) into your own database. You can organize all your selected videos into categories, and also choose the videos to feature.
We are using this app for our own needs and though it would be very helpful for others to have 
The interface to manage videos is very user friendly and uses AJAX when necessary to avoid page refreshes. You can review any video before or after saving it to your database in the dynamic Fancybox player. You can also change any video’s category, feature and unfeature videos, and of course delete any videos you don’t want to have anymore.
Features
– Save your favorite Youtube videos into your own database
– Save your favorite channels
– Search videos by keywords
– Search videos by channels name
– Preview videos title, description and number of views
– Play any video in a fancybox
– Never reload a page when saving your videos !
– Pagination system giving you access to all search results
– Organize your videos by categories
– Ability to add/edit/delete categories
– Ability to delete videos and channels
– Ability to set videos as featured
– Filter your saved videos by categories or featured
– Ribbons effects for Saved and featured videos
– very clean and user friendly backend interface