Beyond the change in experience simply because of the size of the screen, it is important to consider that Flash does not yet run on most mobile devices, that creating a "mobile app" for each platform is a very expensive way to approach training, and that connectivity for mobile devices will change over the next few years.
I believe that mobile devices will soon have the "always-on" connectivity that desktop computers currently have. As soon as enough providers start offering flat-rate plans, you'll see all carriers do so, just as nationwide long-distance is now a standard feature of cell phones. How does this affect the employee? It means that the content does not need to be downloaded ahead of time (like an app). The student will be able to take it just as they would with their desktop browser. Then comes the interesting part of how to create the content. If you stick to web standards, the browsers will be able to provide the optimal display for the specific device. Content built as HTML content (as opposed to text-in-pictures or video movies) can be rearranged by the browser to provide maximum display, and minimum scrolling requirements. Many of the new mobile browsers do a pretty good job of supporting style sheets, so there are a lot of layout options that can be applied.
The ReadyGo Web Course Builder ($499/developer) builds content that is based primarily on HTML and style sheets. The tool includes several templates designed for mobile browsers, and provides a preview of how the course looks in the different display sizes. So, the author can load a mobile template, generate and post the course (see how it looks on mobile devices), and then reload a desktop template, generate and post the course to a different web page (see how it looks on desktop machines), and students can now choose if they want to see the mobile version or the desktop version of the course. The tool can also be used to carry out tests and surveys using the mobile platform. Tracking can be done using the ReadyGo Server Side Testing module ($1499/server). The pricing allows unlimited creation and tracking of courses.