The CART (Central Army Registry for Training) allows you to use the My Training Catalog Search capability of the My Training Tab (MT2), download found materials and view them on your phone. You may login using your AKO username and password or access the documents offline when away from a network.
Depending on the type of information downloaded you may need an external reader to open the file. There are a number of free readers for most formats. If you prefer one stop shopping and don't mind paying you can download "Documents To Go". There is a free version available if you would like to try it before buying, but the free version does not open all files. The full version has a reader for nearly every format you will encounter.