This industry has been around for almost 20 years but people in the Museum and Entertainment industries are only recently starting to realize the potential this software represents to simplifying your everyday lives.
Don't waste your time home-brewing some web-based directory system, or buying hardware without the software solution to drive the system. Buy a complete solution. Digital Signage solutions are characterized by the following key factors: Centrally Managed via the Network, Network Addressable Playback Devices, and Rich Media Playback in 24/7 implementations. Unless you can gaurantee that your home-brew solution can match the results of a Scala Player *OUT OF THE BOX* then you're wasting your time and money.
Hire a consultant to help you find the right solution for your needs. DVD based playback systems are a thing of the past. Today's rich media management systems use archival servers to store motion video and static graphics in a content management system that can be interfaced from a web client that enables the content manager (YOU) to assign media to playback devices, create new messages or sets of content for playback on displays, and create interactive touch systems that are simple to setup and intuitive to use.
In this case I would actually suggest that Scala, Omnivew (Moxie), or Coolsign would all be good candidate products to consider for this application. All three offer fully interactive touch-system setup ability out of the box, and they also integrate their solutions on almost any hardware. Scala specifically now supports everything from WiFi Picture Frames, and Appliance Based RISC Play-back devices to full-blown desktops that drive massive multi-display solutions. Omnivex is great a data integration and information polling for public terminals, and their design system is relative simple to use. Coolsign has a very nice design environment, and their play-back devices range from Displays with Built-in playback devices, to other appliances that can playback a myriad of file formats.
ALL of these providers solution are industry certified and they represent some of the best products in the Digital Signage marketplace today. I would suggest starting with Scala, specifically I would suggest Checking Out one of Scala's biggest resellers that works with Casinos and other large venues. The company name is "Alpha Video - Digital Display Group."
In an ideal world you would store all the content for your playback devices on a central server. That central server would host a web catalogue that you as the administrator could assign content and interactive templates to specific playback devices. The Server would distribute the media assetts to the player systems, and all content would be run locally at the player (screen) to minimize network loads and traffic between the server and players. This type of implementation is called "Push to Playback". The server pushes the content and a playback "schedule" or "script" down to the player, and the player system simply reads the script and displays assetts and touch templates based on parameters outlined by the administrator from the web interface.
Digital signage solutions perform all these functions standard, out of the box. Go do your homework, and find a consultant that can help you make some educated decisions. I work in this industry, but you probably can't afford me.