Sub-Category Listing Page

I have a list of media files (videos) that I have categorized with the name of a software package (because they are tutorials for or about that software) and I have created a category called ‘Apps’ with a sub-category for each app that I have videos/tutorials for.

I would like to create a page/menu that lists all categories that are sub-categories of ‘Apps’ so that I can send users to a page, they can select which app interests them, and that link will send them to a listing of all posts, videos, etc. for that app.

Any ideas?